Detailed description of the invention
Hereinafter, referring to the drawings, being preferred embodiment described in detail the present invention.Further, in explanation, for identical element or have identical function key element use same-sign,The repetitive description thereof will be omitted.
(the 1st embodiment)
With reference to Fig. 1～Figure 10, the manufacture method to the photodiode involved by the 1st embodimentIllustrate.Fig. 1～Figure 10 is in order to the system to the photodiode involved by the 1st embodimentThe figure that the method for making illustrates.
First, prepare by silicon (Si) crystallization constitute and have mutually relative to the 1st interarea 1a andThe n of the 2nd interarea 1b-Type semiconductor substrate 1 (with reference to Fig. 1).n-The thickness of type semiconductor substrate 1Degree is about 300 μm, is 1k Ω about cm than resistance.In present embodiment, so-called " highImpurity concentration ", such as refer to that impurity concentration is 1 × 1017cm-3More than Zuo You, and to conduction typeAdditional "+" represent.So-called " low impurity concentration ", such as, refer to that impurity concentration is 1 × 1015cm-3Below Zuo You, and "-" additional to conduction type represents.As p-type impurity, there is antimony (Sb)Or arsenic (As) etc., as n-type impurity, there is boron (B) etc..
Secondly, at n-1st interarea 1a side of type semiconductor substrate 1 forms p+Type semiconductor regions3 and n+Type semiconductor regions 5 (with reference to Fig. 2).p+Type semiconductor regions 3 is by using central partThe mask etc. of opening, makes the n-type impurity of high concentration at n-From the 1st master in type semiconductor substrate 11a side, face is spread and is formed.n+Type semiconductor regions 5 by use periphery region openings itsIts mask etc., to surround p+The mode of type semiconductor regions 3 makes to compare n-Type semiconductor substrate 1The p-type impurity of higher concentration, at n-From the 1st interarea 1a side diffusion in type semiconductor substrate 1Formed.p+About the thickness of type semiconductor regions 3 for example, 0.55 μm, electrical sheet resistance is for example,44Ω/sq.。n+About the thickness of type semiconductor regions 5 for example, 1.5 μm, electrical sheet resistance is such asIt is 12 Ω/sq..
Secondly, at n-1st interarea 1a side of type semiconductor substrate 1 forms insulating barrier 7 (referenceFig. 3).Insulating barrier 7 is by SiO2Constitute, and by by n-Type semiconductor substrate 1 thermal oxide and shapeBecome.About the thickness of insulating barrier 7 for example, 0.1 μm.Then, at p+Type semiconductor regions 3On insulating barrier 7 in formed contact hole H1, at n+In insulating barrier 7 on type semiconductor regions 5Form contact hole H2.Also the antireflection (AR, anti-reflective) being made up of SiN can be formedLayer replaces insulating barrier 7.
Secondly, at n-On 2nd interarea 1b of type semiconductor substrate 1 and formed blunt on insulating barrier 7Change layer 9 (with reference to Fig. 4).Passivation layer 9 is made up of SiN, and by such as plasma CVD(chemical vapor deposition, chemical gaseous phase deposit) method and formed.The thickness of passivation layer 9Degree for example, 0.1 μm.Then, from the 2nd interarea 1b side to n-Type semiconductor substrate 1 grindsMill, so that n-The thickness of type semiconductor substrate 1 becomes desired thickness (with reference to Fig. 5).ByThis, will be formed in n-Passivation layer 9 on 2nd interarea 1b of type semiconductor substrate 1 removes, andExpose n-Type semiconductor substrate 1.Herein, also the face exposed by grinding is set to the 2nd interarea1b.Desired thickness for example, 270 μm.
Secondly, to n-2nd interarea 1b irradiated with pulse laser PL of type semiconductor substrate 1, shapeBecome irregular concavo-convex 10 (with reference to Fig. 6).Herein, as it is shown in fig. 7, by n-Type is semiconductor-basedPlate 1 is configured in cavity C, and autogamy is placed in the pulse laser generator PLD in the outside of cavity CTo n-Type semiconductor substrate 1 irradiated with pulse laser PL.Cavity C includes gas introduction part GINAndGas discharge section GOUT, by not active gases (such as nitrogen or argon etc.) from gas introduction partGINFrom gas discharge section G after importingOUTDischarge, thus in cavity C, be formed with the most active gasBody stream Gf.By not active gases stream Gf, by dust produced during irradiated with pulse laser PLEtc. being expelled to outside cavity C, and processing bits or dust etc. is prevented to be attached to n-Type semiconductor substrate 1On.
In present embodiment, psec～femtosecond pulse generator is used to produce as pulse laserGenerating apparatus PLD, and throughout whole of the 2nd interarea 1b irradiation psec～femtosecond pulse.2nd interarea 1b is destroyed by psec～femtosecond pulse, as shown in Figure 8, at the 2nd interareaWhole the formation irregular concavo-convex 10 of 1b.Irregular concavo-convex 10 have relative to the 1stDirection that interarea 1a is orthogonal and the face reported to the leadship after accomplishing a task.The difference of height of concavo-convex 10 for example, 0.5～10 μm is leftThe right side, being spaced apart about 0.5～10 μm of the protuberance in concavo-convex 10.Psec～femtosecond pulsePulse temporal width for example, about 50fs～2ps, intensity for example, 4～about 16GW, pulseEnergy for example, 200～800 μ about J/pulse.More generally, peak strength is 3 × 1011～2.5×1013(W/cm2), flux is 0.1～1.3 (J/cm2) left and right.Fig. 8 is to being formed at the 2ndOn interarea 1b irregular concavo-convex 10 carry out SEM (the scanning electron observedMicroscope, sweep electron microscope) image.
Secondly, at n-2nd interarea 1b side of type semiconductor substrate 1 forms accumulation layer 11 (referenceFig. 9).Herein, n is compared to become-The mode of the higher impurity concentration of type semiconductor substrate 1, willP-type impurity is at n-From the 2nd interarea 1b side ion implanting or diffusion in type semiconductor substrate 1, fromAnd form accumulation layer 11.About the thickness of accumulation layer 11 for example, 1 μm.
Secondly, to n-Type semiconductor substrate 1 carries out heat treatment (annealing).Herein, at N2GasUnder the atmosphere of body, with the scope of about 800～1000 DEG C, by n-Type semiconductor substrate 1 heats 0.5～1About hour.
Secondly, after the passivation layer 9 that will be formed on insulating barrier 7 removes, formation electrode 13,15 (with reference to Figure 10).Electrode 13 is formed in contact hole H1, and electrode 15 is formed at contact holeIn H2.Electrode 13,15 is made up of aluminum (Al) etc. respectively, and about thickness for example, 1 μm.Thus, photodiode PD1 is completed.
As shown in Figure 10, photodiode PD1 includes n-Type semiconductor substrate 1.At n-Type half1st interarea 1a side of conductor substrate 1 is formed with p+Type semiconductor regions 3 and n+Type semiconductor regionTerritory 5, at n-Type semiconductor substrate 1 and p+It is formed with pn-junction between type semiconductor regions 3.ElectricityPole 13 is by contact hole H1 and p+Type semiconductor regions 3 is in electrical contact and connects.Electrode 15By contact hole H2 and n+Type semiconductor regions 5 is in electrical contact and connects.
At n-2nd interarea 1b of type semiconductor substrate 1 is formed with irregular concavo-convex 10.?n-2nd interarea 1b side of type semiconductor substrate 1 is formed with accumulation layer 11, and the 2nd interarea 1bExpose optically.So-called 2nd interarea 1b exposes optically, refers not only to the 2nd interarea 1bContact with the atmosphere gas of air etc., and be also included within the 2nd interarea 1b and be formed opticallyThe situation of transparent film.
In photodiode PD1, it is formed with irregular concavo-convex 10 at the 2nd interarea 1b.CauseThis, as shown in figure 11, be incident to the light L of photodiode PD1 by concavo-convex 10 reflections, dissipatePenetrate or spread, and at n-The distance that in type semiconductor substrate 1, traveling is longer.
Generally, relative to refractive index n=3.5 of Si, refractive index n=1.0 of air.Photoelectricity two poleGuan Zhong, at light in the case of the direction incidence vertical with light entrance face, not at photodiodeIn (silicon substrate), absorbed light is divided into the light component by the backside reflection of light entrance face and thoroughlyCross the light component of photodiode.Light through photodiode is helpless to the spirit of photodiodeSensitivity.If the light component reflected by the back side of light entrance face is absorbed in photodiode,Then become photoelectric current.Unabsorbed light component is at light entrance face, with the back of the body arriving light entrance faceThe light component in face similarly reflects or passes through.
In photodiode PD1, at light L from vertical with light entrance face (the 1st interarea 1a)In the case of the incidence of direction, it is formed at irregular concavo-convex the 10 of the 2nd interarea 1b, then if arrivingTo become light component that the angle of more than 16.6 ° arrives by concavo-convex with the exit direction from concavo-convex 1010 total reflections.Because concavo-convex 10 are irregularly formed, have respectively accordingly, with respect to exit directionPlant angle, the light component one way or another diffusion of total reflection.Therefore, in the light component of total reflectionIf existing by n-The light component of type semiconductor substrate 1 absorbed inside, then exist and arrive the 1st interarea1a and the light component of side.
Arrive the light component of the 1st interarea 1a and side due to the diffusion on concavo-convex 10 and towards eachAdvance in direction.Therefore, arrive the light component of the 1st interarea 1a and side by the 1st interarea 1a andThe probability of side total reflection is high.The light component being totally reflected by the 1st interarea 1a and side makes notRepeatedly, its travel distance becomes longer in the same total reflection on face.It is incident to photodiode PD1Light L at n-Advance period of longer distance in the inside of type semiconductor substrate 1, by n-Type halfConductor substrate 1 absorbs, and is detected as photoelectric current.
Being incident to the light L of photodiode PD1, its major part will not pass through photodiodePD1, but travel distance is elongated, by n-Type semiconductor substrate 1 absorbs.Therefore, photoelectricity two poleIn pipe PD1, the spectral sensitivity characteristic at HONGGUANG～the wave band of near infrared light improves.
The 2nd interarea 1b formed well-regulated concavo-convex in the case of, arrive the 1st interarea 1a andThe light component of side is by concavo-convex diffusion, but advances in the same direction.Therefore, the 1st is arrived mainThe probability that the light component of face 1a and side is totally reflected by the 1st interarea 1a and side is relatively low.CauseThis, increase in the 1st interarea 1a and side and then the light component that passes through in the 2nd interarea 1b,The travel distance of the light being incident to photodiode is shorter.It is as a result, it is difficult to improve at near-infraredThe spectral sensitivity characteristic of the wave band of light.
Herein, special for the spectral sensitivity of the wave band near infrared light to the 1st embodimentThe raising effect of property confirms, and is tested.
Make and include the photodiode (referred to as embodiment 1) of above-mentioned composition and not at n-Type half2nd interarea of conductor substrate forms irregular concavo-convex photodiode (referred to as comparative example 1),Research spectral sensitivity characteristic respectively.Embodiment 1 and comparative example 1 are except by the photograph of pulse laserPenetrate and formed irregular concavo-convex beyond, for identical composition.By n-Type semiconductor substrate 1It is dimensioned so as to 6.5mm × 6.5mm.By p+The type semiconductor regions 3 i.e. chi of light-sensitive areaVery little it is set as 5.8mm × 5.8mm.The bias voltage VR applying photodiode is set as0V。
The results are shown in Figure 12.In fig. 12, the spectral sensitivity characteristic of embodiment 1Represented by T1, the spectral sensitivity characteristic of comparative example 1 is by represented by characteristic T2.At Figure 12In, the longitudinal axis represents spectral sensitivity (mA/W), and transverse axis represents the wavelength (nm) of light.With oneThe spectral sensitivity characteristic that personality presentation quantum efficiency (QE) is 100% represented by chain-dotted line,With the spectral sensitivity characteristic that personality presentation quantum efficiency is 50% represented by dotted line.
According to Figure 12, such as under 1064nm, in comparative example 1, spectral sensitivity is 0.2A/W (QE=25%), in contrast, spectral sensitivity is 0.6A/W in embodiment 1(QE=72%), the spectral sensitivity at the wave band of near infrared light is greatly improved.
Also the temperature characterisitic of the spectral sensitivity in embodiment 1 and comparative example 1 is confirmed.Herein, make atmosphere temperature rise to 60 DEG C from 25 DEG C and study spectral sensitivity characteristic, obtain 60Spectral sensitivity at DEG C is relative to the ratio (temperature coefficient) of the spectral sensitivity at 25 DEG C.WillResult is shown in Figure 13.In fig. 13, the characteristic of the temperature coefficient of embodiment 1 is by T3 instituteRepresenting, the characteristic of the temperature coefficient of comparative example 1 is by represented by characteristic T4.In fig. 13, verticalAxle represents temperature coefficient (%/DEG C), and transverse axis represents the wavelength (nm) of light.
According to Figure 13, such as under 1064nm, in comparative example 1 temperature coefficient be 0.7%/DEG C, in contrast, in embodiment 1 temperature coefficient be 0.2%/DEG C, temperature dependency is relatively low.Generally, if temperature rises, then absorptance increases and band-gap energy reduces, thus, and light splitting spiritSensitivity uprises.In embodiment 1, when room temperature, spectral sensitivity is the highest, therefore,Compared with comparative example 1, the change of the spectral sensitivity caused by temperature rising diminishes.
In photodiode PD1, at n-2nd interarea 1b side of type semiconductor substrate 1 is formedAccumulation layer 11.Thus, the excess not produced by light in the 2nd interarea 1b side is carried outIn conjunction with, dark current can be reduced.Accumulation layer 11 suppresses near the 2nd interarea 1b by lightThe carrier produced is captured by the 2nd interarea 1b.Therefore, the carrier produced by light is hadEffect ground moves towards pn-junction portion, thus can further improve the light detection spirit of photodiode PD1Sensitivity.
In 1st embodiment, after forming accumulation layer 11, to n-Type semiconductor substrate 1 entersRow heat treatment.Thus, n-The crystallinity of type semiconductor substrate 1 is recovered, and can prevent the increasing of dark currentThe unfavorable condition added etc..
In 1st embodiment, to n-After type semiconductor substrate 1 carries out heat treatment, formedElectrode 13,15.Thus, in the case of the metal that electrode 13,15 use fusing point is relatively low,Electrode 13,15 also will not melt due to heat treatment.Its result, can not the impact of heat-treatedAnd it is properly formed electrode 13,15.
In 1st embodiment, irradiate psec～femtosecond pulse, and formed irregular concavo-convex10.Thus, irregular concavo-convex 10 can suitably and easily be formed.
(the 2nd embodiment)
With reference to Figure 14～Figure 16, the manufacturer to the photodiode involved by the 2nd embodimentMethod illustrates.Figure 14～Figure 16 is in order to the photodiode involved by the 2nd embodimentThe figure that illustrates of manufacture method.
In the manufacture method of the 2nd embodiment, until from the 2nd interarea 1b side to n-Type quasiconductorTill substrate 1 is ground, identical with the manufacture method of the 1st embodiment, omission is so farThe explanation of operation only.From the 2nd interarea 1b side to n-Type semiconductor substrate 1 is ground, and makesn-After type semiconductor substrate 1 becomes desired thickness, at n-The 2nd of type semiconductor substrate 1Interarea 1b side forms accumulation layer 11 (with reference to Figure 14).The formation of accumulation layer 11 is implemented with the 1stMode is similarly carried out.About the thickness of accumulation layer 11 for example, 1 μm.
Secondly, to n-2nd interarea 1b irradiated with pulse laser PL of type semiconductor substrate 1, andForm irregular concavo-convex 10 (with reference to Figure 15).The irregular formation of concavo-convex 10 is real with the 1stMode of executing similarly is carried out.
Secondly, in a same manner as in the first embodiment to n-Type semiconductor substrate 1 carries out heat treatment.Then, after the passivation layer 9 that will be formed on insulating barrier 7 removes, form electrode 13,15(with reference to Figure 16).Thus, photodiode PD2 is completed.
In the 2nd embodiment, the most in a same manner as in the first embodiment, photoelectricity two pole it is incident toThe travel distance of the light of pipe PD2 is elongated, and light absorbing distance is the most elongated.Thus, at photoelectricity twoIn the pipe PD2 of pole, it is possible to improve the spectral sensitivity characteristic at HONGGUANG～the wave band of near infrared light.
In 2nd embodiment, the thickness of accumulation layer 11 is more than the irregular height of concavo-convex 10Difference.Therefore, even if being formed after accumulation layer 11, irradiated with pulse laser and formed irregularConcavo-convex 10, accumulation layer 11 the most reliably remains.Therefore, it can be ensured that the effect effect of accumulation layer 11Really.
(the 3rd embodiment)
With reference to Figure 17～Figure 21, the manufacturer to the photodiode involved by the 3rd embodimentMethod illustrates.Figure 17～Figure 21 is in order to the photodiode involved by the 3rd embodimentThe figure that illustrates of manufacture method.
In the manufacture method of the 3rd embodiment, till forming passivation layer 9, real with the 1stThe manufacture method executing mode is identical, the explanation of omission operation hereto.Forming passivation layer 9Afterwards, by n-In type semiconductor substrate 1 and p+The part of type semiconductor regions 3 correspondence is from the 2ndInterarea 1b plays side thinning, and remains the peripheral part (with reference to Figure 17) of this part.n-Type is partly ledThe thinning of structure base board 1 is such as by by using potassium hydroxide solution or TMAHThe alkalescence erosion of (tetramethylammonium hydroxide, tetramethyl ammonium hydroxide solution) etc.Carve the anisotropic etching carried out and carry out.n-The thickness of the part of the thinning of type semiconductor substrate 1About degree for example, 100 μm, about the thickness of peripheral part for example, 300 μm.
Secondly, from the 2nd interarea 1b side to n-Type semiconductor substrate 1 is ground, so that n-TypeThe thickness of the peripheral part of semiconductor substrate 1 becomes desired thickness (with reference to Figure 18).Institute's phaseThickness for example, 270 μm hoped.
Secondly, to n-2nd interarea 1b irradiated with pulse laser PL of type semiconductor substrate 1, andForm irregular concavo-convex 10 (with reference to Figure 19).The irregular formation of concavo-convex 10 is real with the 1stMode of executing similarly is carried out.
Secondly, at n-2nd interarea 1b side of the part of the thinning of type semiconductor substrate 1 is formedAccumulation layer 11 (with reference to Figure 20).The formation of accumulation layer 11 is carried out in a same manner as in the first embodiment.About the thickness of accumulation layer 11 for example, 3 μm.
Secondly, in a same manner as in the first embodiment, to n-Type semiconductor substrate 1 is carried out at heatAfter reason, the passivation layer 9 that will be formed on insulating barrier 7 removes, and forms electrode 13,15 (ginsengAccording to Figure 21).Thus, photodiode PD3 is completed.
In the 3rd embodiment, also in the same manner as the 1st and the 2nd embodiment, it is incident to lightThe travel distance of the light of electric diode PD3 is elongated, and light absorbing distance is the most elongated.Thus, lightIn electric diode PD3, it is possible to improve the spectral sensitivity at HONGGUANG～the wave band of near infrared light specialProperty.
In 3rd embodiment, before forming irregular concavo-convex 10, by n-Type is semiconductor-basedIn plate 1 and p+The thinning from the 2nd interarea 1b side of the part of type semiconductor regions 3 correspondence, andRemain the peripheral part of this part.Thus, can obtain respectively by n-The 1st of type semiconductor substrate 1Interarea 1a and the 2nd interarea 1b side are as the photodiode PD3 of light entrance face.
(the 4th embodiment)
With reference to Figure 22～Figure 24, the manufacturer to the photodiode involved by the 4th embodimentMethod illustrates.Figure 22～Figure 24 is in order to the photodiode involved by the 4th embodimentThe figure that illustrates of manufacture method.
In the manufacture method of the 4th embodiment, until by n-Till type semiconductor substrate 1 thinning,Identical with the manufacture method of the 3rd embodiment, the explanation of omission operation hereto.From the 2ndInterarea 1b side is to n-Type semiconductor substrate 1 is ground, and makes n-Type semiconductor substrate 1 becomes instituteAfter desired thickness, at n-2nd interarea 1b of the part of the thinning of type semiconductor substrate 1Side forms accumulation layer 11 (with reference to Figure 22).The formation of accumulation layer 11 is in a same manner as in the first embodimentGround is carried out.About the thickness of accumulation layer 11 for example, 3 μm.
Secondly, to n-2nd interarea 1b irradiated with pulse laser PL of type semiconductor substrate 1, andForm irregular concavo-convex 10 (with reference to Figure 23).The irregular formation of concavo-convex 10 is real with the 1stMode of executing similarly is carried out.
Secondly, in a same manner as in the first embodiment, to n-Type semiconductor substrate 1 carries out heat treatment.Then, after the passivation layer 9 that will be formed on insulating barrier 7 removes, form electrode 13,15(with reference to Figure 24).Thus, photodiode PD4 is completed.
In the 4th embodiment, also in the same manner as the 1st～the 3rd embodiment, it is incident to photoelectricityThe travel distance of the light of diode PD4 is elongated, and light absorbing distance is the most elongated.Thus, photoelectricityIn diode PD4, it is possible to improve the spectral sensitivity characteristic at HONGGUANG～the wave band of near infrared light.
In 4th embodiment, before forming accumulation layer 11, by n-In type semiconductor substrate 1And p+The thinning from the 2nd interarea 1b side of the part of type semiconductor regions 3 correspondence, and remain and be somebody's turn to doThe peripheral part of part.Thus, can obtain respectively by n-1st interarea of type semiconductor substrate 11a and the 2nd interarea 1b side are as the photodiode PD4 of light entrance face.
(the 5th embodiment)
With reference to Figure 25 and Figure 26, to the photodiode array PDA1 involved by the 5th embodimentComposition illustrate.Figure 25 is roughly to represent photoelectricity two pole involved by the 5th embodimentThe plane graph of pipe array PDA1.Figure 26 is to represent along the photodiode battle array shown in Figure 25The figure that the section of the XXVI-XXVI line of row PDA1 is constituted.
Photodiode array PDA1 is to be laminated with multiple semiconductor layer and insulation on substrate 22Layer forms.As shown in figure 25, photodiode array PDA1 is by many for incidence detected lightIndividual light sense channel CH is formed as the photon meter of rectangular (being 4 × 4 in present embodiment)Number uses multichannel avalanche photodide.Upper face side at photodiode array PDA1 is arrangedThere are signal conductor 23, resistance 24 and electronic pads 25.Substrate 22 is e.g. while being that 1mm is leftRight square shape.Each smooth sense channel CH for example, square shape.
Signal conductor 23 is made up of reading unit 23a, connecting portion 23b and passage peripheral part 23c.Reading unit 23a is transferred from the signal of each smooth sense channel CH output.Connecting portion 23b is by each resistance24 are connected with reading unit 23a.Each passage peripheral part 23c is to surround outside light sense channel CHThe mode distribution in week.Reading unit 23a respectively be configured to clamp this reading unit 23a and adjacent 2The light sense channel CH of row connects, and is connected with electronic pads 25 in its one end.Present embodimentIn, photodiode be configured to 4 × 4 rectangular, therefore, at photodiode array PDA1Upper distribution has two reading units 23a, and it is connected with both of which relative to electronic pads 25.SignalWire 23 is such as made up of aluminum (Al).
Resistance 24 via one end 24a and passage peripheral part 23c for each smooth sense channel CHArrange, and be connected with reading unit 23a via the other end 24b and connecting portion 23b.With phaseMultiple (in present embodiment being 8) resistance 24 and this reading that same reading unit 23a connectsPortion 23a connects.Resistance 24 is such as made up of polysilicon (Poly-Si).
Secondly, with reference to Figure 26, the section composition of photodiode array PDA1 is illustrated.As shown in figure 26, photodiode array PDA1 includes: having conduction type is N-shaped (1 conduction type) the substrate 22 of semiconductor layer, the conduction type that is formed on substrate 22 be pThe p of type (the 2nd conduction type)-Type semiconductor layer 33, it is formed at p-In type semiconductor layer 33Conduction type is the p of p-type+Type semiconductor regions 34, protecting film 36, it is formed at p-Type quasiconductorLayer 33 the separated part 40 that conduction type is N-shaped (the 1st conduction type) and be formed at guarantorAbove-mentioned signal conductor 23 on cuticula 36 and resistance 24.Detected light from the upper face side of Figure 26 orFollowing side is incident.
Substrate 22 includes substrate component S, be formed on substrate component S dielectric film 31 andIt is formed at the n on dielectric film 31+Type semiconductor layer 32.Substrate component S is made up of Si (silicon).Dielectric film 31 is such as by SiO2(silicon oxide) is constituted.n+Type semiconductor layer 32 be made up of Si,And the semiconductor layer that conduction type is N-shaped that impurity concentration is high.n+The thickness of type semiconductor layer 32For example, 1 μm～12 μm.
p-Type semiconductor layer 33 is the epitaxial semiconductor layer that conduction type is p-type that impurity concentration is low.p-Type semiconductor layer 33, constitutes pn-junction at the interface with substrate 22.p-Type semiconductor layer 33 withEach smooth sense channel CH has multiple load making and being produced by the incidence of detected light accordinglyStream carries out the multiplication regions AM of avalanche multiplication.p-The thickness of type semiconductor layer 33 is for example,3 μm～5 μm.p-Type semiconductor layer 33 is made up of Si.Therefore, n+Type semiconductor layer 32 and p-Type semiconductor layer 33 constitutes silicon substrate.
p+The multiplication regions AM of type semiconductor regions 34 and each smooth sense channel CH accordingly,It is formed at p-In type semiconductor layer 33.That is, the stacked direction at semiconductor layer (is simply referred to as belowStacked direction) on be positioned at p+The p of the lower section of type semiconductor regions 34-Type semiconductor layer 33 withThe region of the near interface of substrate 22 is multiplication regions AM.p+Type semiconductor regions 34 is by SiConstitute.
Separated part 40 is formed between multiple smooth sense channel CH, by each smooth sense channel CHSeparate.That is, separated part 40 with the most corresponding with each smooth sense channel CH and at p-Type halfConductor layer 33 is formed with the mode of multiplication regions AM and is formed.Separated part 40 is each to surround completelyThe mode of the surrounding of multiplication regions AM and be formed as two-dimensional lattice shape on substrate 22.Separated part40 in the stacking direction from p-The upper face side of type semiconductor layer 33 is through to be formed to following side.PointImpurity from portion 40 is such as made up of P, and this separated part 40 is the conductive-type that impurity concentration is highType is the semiconductor layer of N-shaped.If forming separated part 40 by diffusion, then need longer heatThe process time.Accordingly, it is considered to make n+The impurity of type semiconductor layer 32 is towards epitaxial semiconductor layerSpread and make to rise on the interface of pn-junction.In order to prevent this rising, it is possible to being equivalent to separated partAfter carrying out trench etch near the central authorities in the region of 40, carry out the diffusion of impurity and form separationPortion 40.Detailed content illustrates in other embodiments, it is possible to form screening in the trenchLight portion, this light shielding part utilizes the material of the light absorbing or reflecting the wave band that light sense channel is absorbedFill and formed.In this case, can prevent by the luminescence caused by avalanche multiplication neighbourThe crosstalk that the light sense channel connect impacts and occurs.
p-Type semiconductor layer 33, p+Type semiconductor regions 34 and separated part 40 are in photodiode battle arrayThe upper face side of row PDA1 forms plane, and is formed on protected film 36.Protecting film 36Such as being formed by insulating barrier, this insulating barrier is by SiO2Constitute.
Protecting film 36 is formed signal conductor 23 and resistance 24.The reading of signal conductor 23Portion 23a and resistance 24 are formed at the top of separated part 40.
Signal conductor 23 is as anode function, it is possible to (do not have in the following side of substrate 22Have the side of dielectric film 31) whole face include omit diagram transparent electrode layer (such as by ITOThe layer that (Indium Tin Oxide) is constituted) as negative electrode.Or, as negative electrode, it is also possible toTo form electrode portion from the derivative mode of face side.
Herein, with reference to Figure 27, to each smooth sense channel CH and signal conductor 23 and resistance 24Annexation illustrate.Figure 27 is in order to each smooth sense channel CH and signal conductor 23And the figure that the annexation of resistance 24 roughly illustrates.As shown in figure 27, each light detectionThe p of channel C H+Type semiconductor regions 34 is direct with signal conductor 23 (passage peripheral part 23c)Connect.Thus, signal conductor 23 (passage peripheral part 23c) and p-Type semiconductor layer 33 is electricalConnect.p-Type semiconductor layer 33 and the one end 24a of resistance 24 are (logical via signal conductor 23Road peripheral part 23c) and connect, the other end 24b of resistance 24 is respectively via connecting portion 23bAnd be connected with reading unit 23a.
By the region being formed with multiple smooth sense channel CH of substrate 22 from substrate component S sideThinning, corresponding with the region being formed with multiple smooth sense channel CH by substrate component SPart removes.Around the region of thinning, substrate component S exists as frame portion.AlsoCan have a following composition: also above-mentioned frame portion is removed and by the whole region thinning of substrate 22, i.e.Substrate component S entirety is removed.The removing of substrate component S can (such as dry type be lost by etchingCarve) or grinding etc. and carry out.In situation about substrate component S being removed by dry-etchingUnder, dielectric film 31 also serves as etch stop layer function.Reveal by removing substrate component SThe dielectric film 31 gone out removes in the following manner.
At n+The surface of type semiconductor layer 32, throughout the district being formed with multiple smooth sense channel CHTerritory is overall and is formed with irregular concavo-convex 10.n+Being formed in the surface of type semiconductor layer 32Expose the irregular area optical of concavo-convex 10.So-called n+The surface of type semiconductor layer 32Expose optically, refer not only to n+The surface of type semiconductor layer 32 connects with the atmosphere gas of air etc.Touch, and be also included within n+Optically transparent film it is formed with on the surface of type semiconductor layer 32Situation.Irregular concavo-convex 10 also can only be formed at and each smooth region relative for sense channel CH.
Irregular concavo-convex 10 are formed by following manner: reveal by removing substrate component SThe dielectric film 31 gone out, irradiated with pulse laser in the same manner as above-mentioned embodiment.That is, if to exposingDielectric film 31 irradiated with pulse laser, then dielectric film 31 is removed, and n+Type semiconductor layerThe surface of 32 is destroyed by pulse laser, and forms irregular concavo-convex 10.Irradiated with pulse laserPulse laser generator can use psec～femtosecond pulse generator.Irregular recessedConvex 10 have relative to n+The direction of the surface normal of type semiconductor layer 32 and the face reported to the leadship after accomplishing a task.About the difference of height of concavo-convex 10 for example, 0.5～10 μm, being spaced apart of the protuberance in concavo-convex 10About 0.5～10 μm.The pulse temporal width of psec～femtosecond pulse for example, 50fs～2psLeft and right, intensity for example, 4～about 16GW, pulse energy for example, 200～800 μ J/pulse is leftRight.More generally, peak strength is 3 × 1011～2.5 × 1013(W/cm2), flux is 0.1～1.3(J/cm2) left and right.
Preferably, form irregular concavo-convex 10 in irradiated with pulse laser after, to substrate 22Carry out heat treatment (annealing).Such as, at N2With about 800～1000 DEG C under the atmosphere of gasScope, heats about 0.5～1.0 hour by substrate 22.By above-mentioned heat treatment, n+Type is partly ledThe crystallinity of body layer 32 is recovered, and can prevent the unfavorable condition of the increase etc. of dark current.
In the feelings that the photodiode array constituted in the above described manner PDA1 is used for photon countingUnder condition, under the operation condition of referred to as Geiger mode angular position digitizer, carry out action.When this Geiger mode angular position digitizer action,Each smooth sense channel CH is applied (such as more than 50V) more higher than avalanche voltage revers voltage.If detected light is incident to each smooth sense channel CH, then detected light from upper face side in this conditionAbsorbed at each smooth sense channel CH and produced carrier.Produced carrier is along each lightIt is mobile that electric field one side in sense channel CH accelerates one side, carries out again at each multiplication regions AMIncrease.Then, the carrier through doubling, via resistance 24, is taken out to by signal conductor 23Outside, detects according to the peak value of this output signal.Self-inspection is measured the passage of photon and all can be obtainedObtain the output of equivalent, therefore, exported from the total of all passages by detection, and to from photoelectricityThere is output and count in the several smooth sense channel CH in diode array PDA1.Therefore,In photodiode array PDA1, by the once irradiating of detected light, photon meter can be realizedNumber.
But, in photodiode array PDA1, at n+The surface of type semiconductor layer 32 is formedHave irregular concavo-convex 10.Therefore, the light of photodiode array PDA1 it is incident to by concavo-convex10 reflections, scatter or spread, and longer distance of advancing in photodiode array PDA1.
Such as, photodiode array PDA1 is being used as surface incident type photodiode battle arrayRow, and in the case of light self-insurance cuticula 36 side is incident to photodiode array PDA1, if arrivingReach and be formed at n+On the surface of type semiconductor layer 32 irregular concavo-convex 10, then with from recessedThe light component that the exit direction of convex 10 becomes the angle of more than 16.6 ° to arrive is totally reflected by concavo-convex 10.Because concavo-convex 10 are irregularly formed, accordingly, with respect to exit direction, there is various angle, entirelyThe light component one way or another diffusion of reflection.Therefore, in the light component of total reflection, if exist by, then there is surface and the n arriving protecting film 36 side in the light component that each smooth sense channel CH absorbs+The light component of the side of type semiconductor layer 32.
Arrive surface and the n of protecting film 36 side+The light component of the side of type semiconductor layer 32 passes throughDiffusion on concavo-convex 10 and one way or another is advanced.Therefore, the table of protecting film 36 side is arrivedFace and n+The light component of the side of type semiconductor layer 32 is by the surface of protecting film 36 side and n+Type halfThe probability of the side total reflection of conductor layer 32 is high.By surface and the n of protecting film 36 side+TypeThe light component of the side total reflection of semiconductor layer 32 makes the total reflection in different faces repeatedly, its rowEnter distance and become longer.It is incident to the light of photodiode array PDA1 in photodiode battle arrayAdvancing the period of longer distance in the inside arranging PDA1, each smooth sense channel CH absorbs,And be detected as photoelectric current.
Photodiode array PDA1 is being used as back surface incident type photodiode array, andLight is from n+The face side of type semiconductor layer 32 is incident to the situation of photodiode array PDA1Under, incident light is scattered by concavo-convex 10, and towards each side in photodiode array PDA1To traveling.Arrive surface and the n of protecting film 36 side+The light component of the side of type semiconductor layer 32By the diffusion on concavo-convex 10, one way or another is advanced.Therefore, protecting film 36 side is arrivedSurface and n+The probability pole that the light component of the side of type semiconductor layer 32 is totally reflected by each faceHigh.By surface and the n of protecting film 36 side+The light component of the side total reflection of type semiconductor layer 32Make the total reflection in different faces and concavo-convex 10 reflection, scatter or spread repeatedly, its advanceDistance becomes longer.Be incident to the light of photodiode array PDA1 by concavo-convex 10 reflections, dissipatePenetrate or spread, and longer distance of advancing in photodiode array PDA1, each light examineSurvey channel C H to absorb, and be detected as photoelectric current.
Being incident to the light L of photodiode array PDA1, its major part will not pass through photoelectricity two polePipe array PDA1, travel distance is elongated, each smooth sense channel CH absorb.Therefore, photoelectricityIn diode array PDA1, the spectral sensitivity characteristic at HONGGUANG～the wave band of near infrared light improves.
In 5th embodiment, at n+The surface of type semiconductor layer 32 is formed irregular concavo-convex10.Therefore, do not produced by light in the above-mentioned face side being formed with irregular concavo-convex 10Excess carry out in conjunction with, dark current can be reduced.n+Type semiconductor layer 32 is as accumulation layerFunction, suppression is at n+The load that the above-mentioned near surface of type semiconductor layer 32 is produced by lightStream is captured by this surface.Therefore, the carrier produced by light is effectively towards multiplication regionTerritory AM moves, thus can improve the light detection sensitivity of photodiode array PDA1.
In 5th embodiment, also at n+In type semiconductor layer 32 with multiple smooth sense channelsSurface corresponding between CH is formed with irregular concavo-convex 10, and this surface optical ground dewGo out.Therefore, the light being incident between multiple smooth sense channel CH is also by irregular concavo-convex 10Reflect, scatter or spread, arbitrary light sense channel CH absorb.Therefore, detect at lightBetween channel C H, detection sensitivity will not decline, the light inspection of photodiode array PDA1Survey sensitivity to improve further.But, in the 5th embodiment, it is formed with the detection of multiple light logicalRoad CH, each smooth sense channel CH do not detect the incoming position of light, but it is logical to take the detection of each lightThe output of road CH and as output.Therefore, the crosstalk between each smooth sense channel CH will not becomeFor problem, incident light can be detected by arbitrary light sense channel CH.
In 5th embodiment, n+The thickness of type semiconductor layer 32 is more than irregular concavo-convex 10Difference of height.Therefore, it can reliably ensure that n+The work as accumulation layer of type semiconductor layer 32Use effect.
In photodiode array PDA1, pn-junction is by the n of substrate 22+Type semiconductor layer 32,With the n being formed at this substrate 22+The p as epitaxial semiconductor layer in type semiconductor layer 32-TypeSemiconductor layer 33 is constituted.Multiplication regions AM is formed at the p realizing pn-junction-Type semiconductor layerThe corresponding with each smooth sense channel CH of 33, each multiplication regions AM is by being formed at light inspectionSurvey the separated part 40 between channel C H and realize.Pn-junction face is by n+Type semiconductor layer 32 and p-TypeThe interface of semiconductor layer 33 and separated part 40 and p-The interface of type semiconductor layer 33 is constituted.Therefore, there is not high concentration impurity and become protruding and that electric field uprises region.Therefore, lightElectric diode array PDA1 does not have what the generation edge when carrying out action with Geiger mode angular position digitizer collapsedThe end (edge) of pn-junction.Therefore, without relative to each light in photodiode array PDA1The pn-junction of sense channel CH and protection ring is set.Thus, photodiode battle array it is remarkably improvedThe aperture opening ratio of row PDA1.
By improving aperture opening ratio, thus photodiode array PDA1 also can increase detection effectRate.
Because being separated by separated part 40 between each smooth sense channel CH, therefore, can be wellSuppression crosstalk.
Carry out action with Geiger mode angular position digitizer, and have the light sense channel of photon with the most incident in incidenceIn the case of between the passage of photon, voltage difference becomes greatly, because being formed between light sense channel CHThere is separated part 40, therefore, it is possible to separated by interchannel fully.
In photodiode array PDA1, reading unit 23a of signal conductor 23 is formed at separationThe top in portion 40, therefore, suppression signal conductor 23 crosses i.e. light inspection above multiplication regions AMOn survey face.Therefore, aperture opening ratio improves further.And then, it is believed that the most effective to suppression dark current.In photodiode array PDA1, resistance 24 is also formed in the top of separated part 40, therefore,Aperture opening ratio improves further.
Use the semiconductor substrate of N-shaped, and be formed on the epitaxial semiconductor layer of p-typeIn the case of, it may occur that the part in electric hole produced on the semiconductor substrate of N-shaped postpone intoEntering multiplication regions and become the problem of residual impulse, above-mentioned situation is that the present application person is according to surplusThe wavelength dependency of after pulse and find.For the problems referred to above, at photodiode arrayIn PDA1, because in the region being formed with multiple smooth sense channel CH, substrate component S being removedGo, therefore, residual impulse can be suppressed.
Separated part 40 in 5th embodiment can apply various deformation.Figure 28 is outline earth's surfaceShow the section of the 1st variation of photodiode array PDA1 involved by the 5th embodimentThe figure constituted.In photodiode array involved by 1st variation, multiple (these variationIn be two) separated part 40 is formed between light sense channel CH.
Figure 29 is roughly to represent the photodiode array PDA1 involved by present embodimentThe figure that the section of the 2nd variation is constituted.In photodiode array involved by 2nd variation,Separated part 40 is only formed at above near (the detected light plane of incidence), and the most in the stacking directionFrom p-The upper face side of type semiconductor layer 33 is through to following side.
In above-mentioned embodiment, epitaxial semiconductor layer is set to the 2nd conduction type, but also can be byEpitaxial semiconductor layer is set to the 1st conduction type, arranges the 2nd conduction type in this semiconductor layerSemiconductor regions, by the half of the epitaxial semiconductor layer of the 1st conduction type and the 2nd conduction typeConductive region constitutes pn-junction.
As shown in Figure 39 and Figure 40, photodiode array PDA1 is installed on substrate WB.In Figure 39, waited by bonding and photodiode array PDA1 be fixed on substrate WB,And engaged by lead-in wire and be electrically connected with the distribution being formed on substrate WB.In Figure 40, logicalCross projection to be fixed on substrate WB by photodiode array PDA1, and be formed at baseDistribution on plate WB is electrically connected with.By projection by photodiode array PDA1 withIn the case of substrate WB connects, it is preferably at photodiode array PDA1 and substrate WBBetween fill underfill resin.In this case, it can be ensured that photodiode array PDA1Bonding strength with substrate WB.
In Figure 39, photodiode array PDA1 is being used as back surface incident type photoelectricity two poleIn the case of pipe array, preferably substrate WB is optically transparent.Equally, in Figure 40,In the case of photodiode array PDA1 is used as surface incident type photodiode array,Preferably also substrate WB is optically transparent.Now, the underfill tree filled it is preferablyFat is also optically transparent.
(the 6th embodiment)
With reference to Figure 30, the structure to the photodiode array PDA2 involved by the 6th embodimentOne-tenth illustrates.Figure 30 is roughly to represent the photodiode battle array involved by the 6th embodimentThe figure that the section of row PDA2 is constituted.Photodiode array involved by 6th embodimentPDA2 includes aspect and the photoelectricity two involved by the 5th embodiment of light shielding part in separated part 40Pole pipe array PDA1 is different.
As shown in figure 30, separated part 40 includes light shielding part 42, and this light shielding part 42 is by absorbing by lightThe light of the wave band (visible ray is near infrared light) of the detected light that sense channel CH is detectedMaterial is constituted.Light shielding part 42 is imbedded and is formed as from p to separated part 40-Type semiconductor layer 33The core that extends towards following side of upper face side.Light shielding part 42 has such as been mixed into by photoresistThe dyestuff of black or through the gold of the black photoresist of the pigment such as carbon black of insulation processing or tungsten etc.Belong to and constituting.Wherein, the material at composition light shielding part 42 is not the megohmite insulant (gold of such as tungsten etc.Belong to) in the case of, need to utilize SiO2Deng dielectric film this light shielding part 42 is carried out overlay film.The5 embodiments describing the most, if forming separated part 40 by diffusion, then needing longerHeat treatment time, therefore considers have n+The impurity of type semiconductor layer 32 is towards epitaxial semiconductor layerDiffusion, and make to rise on the interface of pn-junction.In order to prevent this rising, it is possible to being equivalent to separateAfter carrying out trench etch near the central authorities in the region in portion 40, carry out the diffusion of impurity and formed pointFrom portion 40.As shown in figure 30, after carrying out impurity diffusion, n is become+Type semiconductor layer 32 withThe shape that separated part 40 is connected.As mentioned above, it is possible in remaining groove, form light shielding part,This light shielding part utilize the light of the wave band that absorbing light sense channel absorbed material (as described below,It is alternatively the material of the light of the wave band that reflection light sense channel is absorbed) fill and formed.This prevents and by the luminescence caused by avalanche multiplication, adjacent light sense channel is impactedAnd the crosstalk occurred.
In the 6th embodiment, the most in a same manner as in the fifth embodiment, photoelectricity two pole it is incident toThe travel distance of the light of pipe array PDA2 is elongated, and light absorbing distance is the most elongated.Thus, lightIn electric diode array PDA2, it is possible to improve sensitive in the light splitting of HONGGUANG～the wave band of near infrared lightDegree characteristic.It addition, dark current can be reduced, and can improve photodiode array PDA2'sLight detection sensitivity.
In photodiode array PDA2, also in the same manner as photodiode array PDA1,Not there is the end (edge) of the pn-junction that edge collapse occurs when carrying out action with Geiger mode angular position digitizer.Therefore, without the pn relative to each smooth sense channel CH in photodiode array PDA2Tie and protection ring is set.Thus, the aperture opening ratio of photodiode array PDA2 can be improved.
By improving aperture opening ratio, and in photodiode array PDA2, also can increase detection effectRate.
Because utilizing separated part 40 will to separate between each smooth sense channel CH, therefore, can be wellSuppression crosstalk.
In photodiode array PDA2, reading unit 23a of signal conductor 23 is formed at separationThe top in portion 40, therefore, aperture opening ratio improves further.And then, it is believed that to suppression dark current alsoEffectively.
Each separated part 40 includes light shielding part 42, and this light shielding part 42 is by absorbing by light sense channel CHThe material of the light of the wave band of the detected light detected is constituted.Therefore, detected light is by light shielding partAbsorb, thus can favorably inhibit the generation of crosstalk.Light shielding part 42 is by absorbing by light sense channelThe wave band of the detected light that CH is detected, the visible ray produced especially by avalanche multiplication～The material of the light of the wave band of near infrared light is constituted, so that the light produced by avalanche multiplication will notAdjacent light sense channel CH is impacted.Therefore, can favorably inhibit the generation of crosstalk.
Light shielding part 42 is not limited to absorb visible ray to the material of the light of near infrared light, it is possible to forReflection visible ray is to the material of the light of near infrared light.In this case, because detected light is by hidingLight portion is reflected, and therefore, can favorably inhibit the generation of crosstalk.Light shielding part 42 is examined by light by reflectionSurvey the wave band of the detected light that channel C H is detected, produce especially by avalanche multiplicationThe material of the light of the wave band of visible ray～near infrared light is constituted, so that being produced by avalanche multiplicationAdjacent light sense channel CH will not be impacted by light.Therefore, can favorably inhibit crosstalkGeneration.
Light shielding part 42 is not limited to absorb or reflection visible ray is to the material of the light of near infrared light,As long as by absorbing or the light of the wave band of detected light that reflection is detected by light sense channel CHMaterial.Wherein, it is preferable that light shielding part 42 is by absorbing or reflect by light sense channel CH instituteThe wave band of detected light, the visible ray produced especially by avalanche multiplication～the near-infrared of detectionThe material of the light of the wave band of light is constituted, so that the light produced by avalanche multiplication will not be to adjacentLight sense channel CH impact.
Light shielding part 42 also can be made up of the material that refractive index ratio separated part 40 is lower.In this situationUnder, because light is reflected by light shielding part, therefore, it is possible to suppress the generation of crosstalk well.
(the 7th embodiment)
With reference to Figure 31, the structure to the photodiode array PDA3 involved by the 7th embodimentOne-tenth illustrates.Figure 31 is in order to the photodiode array involved by the 7th embodimentThe section of PDA3 constitutes the figure roughly illustrated.Photoelectricity two involved by 7th embodimentThe aspect that pole pipe array PDA3 is formed on silicon nitride film at signal conductor 23 and the 5th embodiment partyPhotodiode array PDA1 involved by formula is different.
As shown in figure 31, photodiode array PDA3 includes: having conduction type is N-shapedThe substrate 22 of the semiconductor layer of (the 1st conduction type), the conduction type being formed on substrate 22For p-type (the 2nd conduction type) p-type semiconductor layer 35, be formed at p-type semiconductor layer 35On the p that conduction type is p-type+Type semiconductor regions 34, protecting film 36a, 36b, it is formed atConduction type in p-type semiconductor layer 35 be N-shaped (the 1st conduction type) separated part 40,The signal conductor 23 being made up of aluminum and the resistance 24 being such as made up of Poly-Si.
Substrate 22 includes n+The substrate component (not shown) of type and being formed on this substrate componentN-type semiconductor layer 32.
P-type semiconductor layer 35 is that impurity concentration compares p+The conduction type that type semiconductor regions 34 is lowerEpitaxial semiconductor layer for p-type.P-type semiconductor layer 35, in the n-type semiconductor with substrate 22The interface of layer 32 constitutes pn-junction.P-type semiconductor layer 35 is with each smooth sense channel CH accordinglyBe there is multiple carrier making to be produced by the incidence of detected light and carry out the multiplication of avalanche multiplicationRegion AM.P-type semiconductor layer 35 is made up of Si.
P-type semiconductor layer 35, p+Type semiconductor regions 34 and separated part 40 are in photodiode battle arrayThe upper face side of row PDA3 forms plane, and is formed on protected film 36a, 36b.ProtectionFilm 36a is by by silicon oxide film (SiO2Film) dielectric film that constitutes formed, protecting film 36bBy by silicon nitride (SiN film or Si3N4Film) dielectric film that constitutes formed.
As shown in figure 31, separated part 40 is sequentially laminated with protecting film 36a, resistance 24,Protecting film 36b and signal conductor 23.Specifically, separated part 40 is laminated with protecting film36a.Protecting film 36a is laminated with resistance 24.On protecting film 36a and resistance 24, removeOutside a part for each resistance 24, it is laminated with protecting film 36b.Protecting film 36b and on non-layerIn a part for the resistance 24 of folded protecting film 36b, it is laminated with signal conductor 23 to carry out electricallyConnect.Specifically, between resistance 24, reading unit 23a of signal conductor 23 it is laminated with, at electricityIt is laminated with in resistance 24 and leads as the signal with connecting portion 23b or passage peripheral part 23c electric connectionLine 23 is to be electrically connected with.
As shown in figure 31, at p+Except the protected film of a part of outer stack on type semiconductor regions 3436b.P at non-stacked guard film 36b+In this part of type semiconductor regions 34 and layerIt is laminated on p+In a part of protecting film 36b on type semiconductor regions 34, it is laminated with signal conductorThe passage peripheral part 23c of 23 is to be electrically connected with.
In the 7th embodiment, also in the same manner as the 5th and the 6th embodiment, it is incident to lightThe travel distance of the light of electric diode array PDA3 is elongated, and light absorbing distance is the most elongated.ByThis, in photodiode array PDA3, it is possible to improve the wave band at HONGGUANG～near infrared lightSpectral sensitivity characteristic.It addition, dark current can be reduced, and photodiode array can be improvedThe light detection sensitivity of PDA3.
In photodiode array PDA3, also in the same manner as photodiode array PDA1,Not there is the end (edge) of the pn-junction that edge collapse occurs when carrying out action with Geiger mode angular position digitizer.Therefore, without the pn relative to each smooth sense channel CH in photodiode array PDA3Tie and protection ring is set.Thus, the aperture opening ratio of photodiode array PDA3 can be improved.
By improving aperture opening ratio, photodiode array PDA3 also can increase detection efficiency.
Because utilizing separated part 40 will to separate between light sense channel CH, thus can favorably inhibitCrosstalk.
In photodiode array PDA3, reading unit 23a of signal conductor 23 is also formed in pointFrom the top in portion 40, therefore, aperture opening ratio improves further.And then, it is believed that to suppression dark currentThe most effective.
Signal conductor 23 is made up of aluminum, it is thus possible, for instance in the case of being formed on oxide-film,Can occur to penetrate into the problem to the film under it owing to applying high voltage and aluminum.Reply the problems referred to above,In photodiode array PDA3, signal conductor 23 is formed at and is made up of silicon nitride filmOn protecting film 36b.Therefore, even if photodiode array PDA3 being applied high voltage, alsoAluminum can be suppressed to penetrate into the film (protecting film 36b) under it.
Under reading unit 23a of signal conductor 23, it is laminated with protecting film 36b and protecting film 36aOr resistance 24.Therefore, can favorably inhibit and penetrate into separated part 40 owing to applying high voltage and aluminumAnd p-type semiconductor layer 35.
In photodiode array PDA3, even if in the case of applying is high-tension, it is possible to veryAluminum is suppressed well to invade to light sense channel CH and separated part 40.
The resistance 24 being made up of such as polysilicon (Poly-Si) is formed on protecting film 36a, andAnd on this resistance 24, it is formed with protecting film 36b and signal conductor 23.
The semiconductor layer being used as p-type replaces n-type semiconductor layer 32.In this case, existThe semiconductor layer of this p-type and n+Pn-junction is constituted between the substrate component S (substrate 22) of type, andMultiplication portion AM is formed in the semiconductor layer of this p-type.
(the 8th embodiment)
With reference to Figure 32, the structure to the photodiode array PDA4 involved by the 8th embodimentOne-tenth illustrates.Figure 32 is roughly to represent the photodiode battle array involved by the 8th embodimentThe figure that the section of row PDA4 is constituted.Photodiode array involved by 8th embodimentPDA4 is not including aspect and the photodiode involved by the 5th embodiment of separated part 40Array PDA1 is different.
As shown in figure 32, p-Type semiconductor layer 33 is with each multiplication regions AM and each smooth sense channelMode mutually corresponding for CH has multiple multiplication regions AM.Shape between each smooth sense channel CHBecome to have signal conductor 23 and resistance 24.
In the 8th embodiment, also in the same manner as the 5th～the 7th embodiment, it is incident to photoelectricityThe travel distance of the light of diode array PDA4 is elongated, and light absorbing distance is the most elongated.Thus,In photodiode array PDA4, it is possible to improve the light splitting spirit at HONGGUANG～the wave band of near infrared lightSensitivity characteristic.It addition, dark current can be reduced, and photodiode array PDA4 can be improvedLight detection sensitivity.
In photodiode array PDA4, also in the same manner as photodiode array PDA1,Not there is the end (edge) of the pn-junction that edge collapse occurs when carrying out action with Geiger mode angular position digitizer.Therefore, without the pn relative to each smooth sense channel CH in photodiode array PDA4Tie and protection ring is set.Thus, the aperture opening ratio of photodiode array PDA4 can be improved.EnterAnd, owing to photodiode array PDA4 does not include separated part, thus can show higherAperture opening ratio.
By improving aperture opening ratio, thus in photodiode array PDA4, also can increase detectionEfficiency.
In photodiode array PDA4, reading unit 23a of signal conductor 23 is formed at each lightBetween sense channel CH, therefore, aperture opening ratio improves further.And then, it is believed that to suppressing dark electricityFlow the most effective.
Above, being preferred embodiment illustrated the present invention, but, the present invention is alsoIt is not limited to above-mentioned embodiment, without departing from carrying out various change in the range of its purport.
In 1st～the 4th embodiment, throughout whole the irradiated with pulse laser of the 2nd interarea 1b,And form irregular concavo-convex 10, but it is not limited to this.Such as, it is possible to only to n-Type is partly ledIn 2nd interarea 1b of structure base board 1 and p+The area illumination pulse that type semiconductor regions 3 is relativeLaser, and form irregular concavo-convex 10.
In 1st～the 4th embodiment, by electrode 15 be formed at n-The of type semiconductor substrate 1The n of 1 interarea 1a side+Type semiconductor regions 5 is in electrical contact and connects, but is not limited to this.Such as, it is possible to by electrode 15 be formed at n-2nd interarea 1b side of type semiconductor substrate 1Accumulation layer 11 is in electrical contact and connects.In such a situation it is preferred that, at n-Type semiconductor substrate 1The 2nd interarea 1b in and p+Beyond the region that type semiconductor regions 3 is relative, form electrode 15.Its reason is, if at n-In 2nd interarea 1b of type semiconductor substrate 1 and p+Type quasiconductorThe region formation electrode 15 that region 3 is relative, then be formed at the irregular concavo-convex of the 2nd interarea 1b10 are blocked by electrode 15, and occur what the spectral sensitivity in the wave band of near infrared light declined to showAs.
Also can be by the p in photodiode PD1～PD4 involved by the 1st～the 4th embodimentEach conduction type of type and N-shaped replaces with contrary to the above.
In the 5th～the 8th embodiment, it is formed at the light sense channel of photodiode arrayThe quantity (4 × 4) that quantity is not limited in above-mentioned embodiment.It is formed at light sense channel CHBetween the quantity of separated part 40 be also not limited to the number shown in above-mentioned embodiment and variationAmount, the most alternatively more than 3.Signal conductor 23 also can be not formed at the upper of separated part 40Side.Resistance 24 also can be not formed at the top of separated part 40.Each layers etc. are not limited to above-mentionedLayer illustrated in embodiment and variation.Also can be by above-mentioned photodiode arrayP-type and each conduction type of N-shaped in PDA1～PDA4 replace with contrary to the above.
Figure 33 is involved by the variation of the layer structure roughly representing the embodiment shown in Figure 26And photodiode array section constitute figure.Figure 34 is roughly to represent shown in Figure 28Embodiment layer structure the photodiode array involved by variation section constituteFigure.Figure 35 is involved by the variation of the layer structure roughly representing the embodiment shown in Figure 29And photodiode array section constitute figure.Figure 36 is roughly to represent shown in Figure 30Embodiment layer structure the photodiode array involved by variation section constituteFigure.Figure 37 is involved by the variation of the layer structure roughly representing the embodiment shown in Figure 31And photodiode array section constitute figure.Figure 38 is roughly to represent shown in Figure 32Embodiment layer structure the photodiode array involved by variation section constituteFigure.These basic planes constitute same as shown in Figure 25 with annexation.
As it has been described above, in the structure shown in Figure 33 to Figure 38, use n-type semiconductor layer R33Or R35 replaces the p-type of Figure 26, Figure 28, Figure 29, Figure 30, Figure 31, Figure 32 partly to leadBody layer 33 or p-type semiconductor layer 35.In this case, pn-junction is formed at the N-shaped of low concentrationSemiconductor layer R33 (or R35) and the interface of p-type semiconductor region 34, vague and general layer is from pnTying and extend towards n-type semiconductor layer R33 (or R35), multiplication regions AM is right with vague and general layerShould be formed towards n-type semiconductor layer R33 (or R35) from pn-junction interface on ground.Other structureSame as described above with effect.
This photodiode array PDA1～PDA4 is by multiple light detection of incident detected lightChannel C H-shaped Cheng Yu has on the substrate 22 of the N-shaped of n-type semiconductor layer 32.AndIt is to be formed at the multiple smooth sense channel CH of incident detected light to have as the 1st conductive-typeThe n of type+Photodiode array on the substrate of the semiconductor layer 32 (S) of type.MultipleLight sense channel CH includes: substrate 22, n as the 1st conduction type-The extension of type is partly ledBody layer R33 (or R35), p as the 2nd conduction type+The semiconductor regions 34 of type andMultiple resistance 24.Epitaxial semiconductor layer R33 (or R35) is formed at the 1st conduction of substrate 22On the semiconductor layer 32 of type.Epitaxial semiconductor layer R33 (or R35) is with each multiplication regions AMThe mode the most corresponding with each smooth sense channel, is had and makes to be produced by the incidence of detected lightCarrier carry out multiple multiplication regions AM of avalanche multiplication.Outside semiconductor regions 34 is formed atProlong in semiconductor layer R33 (or R35), and with this epitaxial semiconductor layer R33 (or R35)Interface constitute pn-junction.Multiple resistance 24 have two ends, and for each smooth sense channelCH and arrange.Multiple resistance 24 via one end 24a with epitaxial semiconductor layer R33 (orThe semiconductor regions 34 of the 2nd conduction type in R35) is electrically connected with, and via the other endPortion 24b and be connected with signal conductor 23.
As shown in figure 25, resistance 24 is via one end 24a and passage peripheral part 23c, for respectivelyLight sense channel CH and arrange, and via the other end 24b and connecting portion 23b with readingPortion 23a connects.The multiple resistance 24 being connected with identical reading unit 23a are relative to this reading unit23a and connect.
In this photodiode array, pn-junction is partly led by the extension of the 1st conduction type on substrateBody layer R33 (or R35) and be formed in this epitaxial semiconductor layer R33 (or R35)The semiconductor regions 34 of 2 conduction types is constituted.Multiplication regions AM is formed at and realizes pn-junctionIn epitaxial semiconductor layer R33 (or R35), the multiplication regions AM corresponding with each smooth sense channelIt is in this epitaxial semiconductor layer R33 (or R35).
Industrial applicability
The present invention can be used in semiconductor light detecting element and optical detection device.