CN102403369A - Passivation dielectric film for solar cell - Google Patents

Abstract

The invention discloses a passivation dielectric film for a solar cell, which is of a single-layer structure consisting of a first dielectric film or a laminated structure consisting of the first dielectric film and a second dielectric film, wherein the first dielectric film is directly contacted with a silicon substrate material, and the second dielectric film is deposited on the first dielectric film. The passivation dielectric film has good high-temperature sintering resistance and optical antireflection performance, and the manufacturing method has the advantages of wider process window and strong feasibility and is beneficial to large-scale production.

Description

A kind of dielectric passivation film that is used for solar cell

Technical field

The invention belongs to technical field of solar cells, be specifically related to a kind of dielectric passivation film that is used for passivation silicon chip of solar cell surface.

Background technology

Photovoltaic technology is one and utilizes large-area p-n junction diode with the technology of conversion of solar energy for electric energy.This p-n junction diode is called solar cell.The semi-conducting material of manufacturing solar cells all has certain energy gap; When solar cell receives solar radiation; The photon that energy surpasses energy gap produces electron hole pair in solar cell; P-n junction separates electron hole pair, and the asymmetry of p-n junction has determined the flow direction of dissimilar photo-generated carriers, connects outwards power output through external circuit.This is similar with common electrochemical cell principle.

As a rule; The sensitive surface of solar cell often need have this structure of passivated reflection reducing membrane; Can reduce silicon chip surface to reflection of incident light on the one hand, increase of the absorption of silicon body material, thereby the concentration that improves photo-generated carrier increase density of photocurrent sunlight; On the other hand effectively dangle in a large number key and the defective that exist of passivation silicon materials surface (like dislocation; Crystal boundary and point defect etc.); Thereby reduce photo-generated carrier silicon face recombination rate, improve the useful life of minority carrier, thereby promote the lifting of solar cell photoelectric transformation efficiency.Therefore, the quality of improving passivated reflection reducing membrane plays a part crucial for the raising of silion cell performance.

Solar cell inactivating antireflective film material commonly used at present is generally SiNx.On n-type silicon chip surface, the SiNx film has good surface passivation effect.But owing to have certain fixed positive charge in the SiNx thin-film body, SiNx is to the passivation on p type silicon substrate surface and undesirable.Silica (SiOx) film is because the comparatively fine and close good passivation effect of film forming also is one of passivated reflection reducing membrane material of using always.Preparation method commonly used comprises two kinds of thermal oxidation method and wet chemical oxidation.Thermal oxidation method prepares silica and often under the high temperature furnace pipe environment, generates (generally being higher than 900 ℃), and not only complex process but also its high growth temperature process reduce the quality of silicon materials, and it becomes film uniformity to receive silicon substrate material surface properties influence bigger simultaneously.The wet chemical oxidation legal system is equipped with silicon oxide film and then is difficult to the control thickness, is difficult to realize passivation effect preferably.Thereby utilize the direct passivation silicon chip surface of silicon oxide film to be difficult in the solar cell manufacturing process and implement.

For realizing well passivated to p type silicon substrate material; S. Dauwe (Proc. 29th IEEE Photovoltaic Specialists Conf; New Orleans, USA (2002), p.1246) and P. Alternatt (Proceedings of the 21st European Photovoltaic Solar Energy Conference; Dresden (2006); P.647) etc. the people adopts the PECVD method deposition of amorphous silicon films that (is lower than 250 ℃) at low temperatures and is used for passivation p type silicon chip surface, has obtained good effect, and the matrix surface recombination rate obviously reduces.But this amorphous silicon membrane is responsive to high temperature abnormality, and the high-temperature sintering process after the conventional silk screen printing can cause the rapid crystallization of amorphous silicon membrane, loses passivation effect, can not be used for the large solar battery production fully.

Summary of the invention

The purpose of this invention is to provide a kind of dielectric passivation film that is used for solar cell, this deielectric-coating has good passivation effect to P type silicon materials, and preparation method's simple possible, is beneficial to large-scale industrial production.

Above-mentioned purpose of the present invention realizes through following technical scheme: a kind of dielectric passivation film that is used for solar cell; The single layer structure that said passivating film is made up of first deielectric-coating; Or the layered structure formed by first deielectric-coating and second deielectric-coating of said passivating film; Wherein first deielectric-coating directly contacts with the silicon substrate material, and second deielectric-coating is deposited on first deielectric-coating.

Be that passivating film of the present invention can be the single-layer medium structure; Also can be the layered structure of two kinds of deielectric-coating compositions; But second deielectric-coating must deposit on the basis of first deielectric-coating; Above-described dielectric-coating structure can directly apply to the surface passivation of solar cell, thereby improves the useful life of photo-generated carrier, increases the solar cell photoelectric transformation efficiency.

Wherein the first dielectric passivation film directly contacts with the silicon substrate material, is mainly used in the passivation to p type silicon substrate material.When being used for passivation p type material, both can be used to realize passivation to the p type emitter that is positioned at n type solar cell sensitive surface, also can be used for realizing passivation to backlight of p type solar cell.When as the passivating material of battery sensitive surface, deielectric-coating plays the effect of part anti-reflection simultaneously.

First deielectric-coating according to the invention is a metal oxide.

Specifically, said metal oxide the best is aluminium oxide (Al₂O₃).

Wherein said first deielectric-coating must have certain thicknesses of layers scope, and its thickness the best is 3-200nm.

First deielectric-coating according to the invention can prepare through the multiple technologies method; Comprise ald (ALD), conventional chemical vapour deposition (CVD), plasma reinforced chemical vapour deposition (PECVD), metal-organic chemical vapor deposition equipment (MOCVD), molecular beam epitaxy (MBE) or the like; The reacting gas that is adopted comprises a kind of aluminum contained compound at least, like Al (CH₃)₃, AlCl₃, Al (CH₃)₂Cl, (CH₃)₂C₂H₅N:AlH₃Deng.

Second deielectric-coating according to the invention is silicon nitride, carborundum, silica or titanium oxide deielectric-coating, or said second deielectric-coating composite dielectric film that is two or more composition in silicon nitride, carborundum, silica and the titanium oxide.

Be that laminated passivation film structure according to the invention comprises first deielectric-coating and second deielectric-coating; First deielectric-coating that directly contacts with the silicon substrate surface is an aluminium oxide; Second deielectric-coating is deposited on the pellumina, the composite membrane of the multilayer material that second deielectric-coating can form for silicon nitride, carborundum, silica, titanium oxide monofilm or above-mentioned material.

The thickness of second deielectric-coating according to the invention is 3-200 nm,, refractive index is 0.8-3.0.

The present invention's second deielectric-coating can prepare through the multiple technologies method, comprises ald (ALD), conventional chemical vapour deposition (CVD), plasma reinforced chemical vapour deposition (PECVD), metal-organic chemical vapor deposition equipment (MOCVD), molecular beam epitaxy (MBE) or the like.

Be that first deielectric-coating according to the invention and second deielectric-coating adopt ald ALD, chemical vapour deposition (CVD) CVD, PCVD PECVD, metal-organic chemical vapor deposition equipment MOCVD or molecular beam epitaxial growth MBE method to prepare; The reacting gas that is adopted when wherein preparing first deielectric-coating comprises a kind of aluminum contained compound at least, and said aluminum contained compound comprises Al (CH₃)₃, AlCl₃, Al (CH₃)₂Cl or (CH₃)₂C₂H₅N:AlH₃

Deielectric-coating according to the invention is arranged at the sensitive surface of solar cell or is arranged at the shady face of solar cell.

Be that deielectric-coating of the present invention both can be used to realize the passivation to the solar cell sensitive surface; Also can be used for realizing passivation to backlight of solar cell; Like passivation to backlight of p type solar cell or n type solar cell sensitive surface; When as the passivating material of battery sensitive surface, deielectric-coating plays the effect of antireflective film simultaneously.

Except the selection of thin-film material, the surface appearance of matrix can directly have influence on uniformity and the film of the film forming passivation effect to material before the thin film deposition.Therefore, basis material effectively cleaned the quality that significantly to improve deielectric-coating with surface treatment and become film uniformity, improve its inactivating performance and reduce reflection of incident light.

The surface topography of silicon substrate material according to the invention can be burnishing surface or suede structure; Wherein the burnishing surface structure can adopt the chemical solution corrosion to form; Described chemical solution can be the KOH or the NaOH aqueous solution, and its quality percentage composition is 10 ~ 40%, and temperature is 50 ~ 90 ℃; Or described chemical solution can be TMAH or ethylenediamine solution, and its quality percentage composition is 10 ~ 30%, and temperature is 50 ~ 90 ℃; Wherein said suede structure can adopt the chemical solution corrosion to prepare, and said chemical solution is the NaOH aqueous solution, and its quality percentage composition is 0.5 ~ 5%, under 75 ~ 90 ℃ temperature, forms through surface-texturing.

Simultaneously; Before the plated film silicon substrate material is cleaned the effect that can improve thin film passivation among the present invention; Through improving conventional cleaning solution prescription or in solution, adding additive to realize excellent control to the silicon materials surface, strengthen passivation effect, improve the solar cell photoelectric transformation efficiency.

Be that the present invention is on the silicon substrate material of burnishing surface or suede structure before deposition first passivating film at surface topography; Can clean the silicon substrate material surface; Clean the hydrofluoric acid, nitric acid, hydrochloric acid or the sulfuric acid that adopt hydrofluoric acid, nitric acid, hydrochloric acid or sulfuric acid and contain additive; Scavenging period is 0.5-60 minute, and temperature is 5 ~ 90 ℃; Wherein said additive can be selected from organic acid and have one or more the mixture in the silica-based surfactant etc. of hydrophilic and hydrophobic group simultaneously, and its content can be for accounting for the 0.1-15% of sour gross mass., organic acid can be acetate, oxalic acid, lactic acid, ascorbic acid, malic acid or citric acid etc., has hydrophilic and the silica-based surfactant hydrophobic group simultaneously and can be polyether-type siloxanes, polyester-type siloxanes etc.

Compared with prior art, the present invention has following beneficial effect:

(1) passivating film that is used for solar cell provided by the invention; Adopt metal oxide perhaps to adopt laminated deielectric-coating such as aluminium oxide/silicon nitride, alumina/silica, aluminum oxide titanium white as the single-layer medium membrane structure; Passivation p type silicon substrate is surperficial effectively; Improve minority carrier lifetime, improve the photoelectricity conversion performance of crystal silicon solar energy battery;

(2) the dielectric passivation film that is used for solar cell provided by the invention, it has good high temperature resistant sintering and optics anti-reflection performance, manufacture method process window broad, feasibility is strong, is beneficial to large-scale production.

Description of drawings

Fig. 1 is the sectional view that laminated passivating film is applied to n type crystalline silicon solar cell among the embodiment 1, comprises 11, first passivating film; 12, second passivating film; 13, sensitive surface Metal Contact; 14, p+ emitter; 15, n+BSF; 16, shady face Metal Contact; 17, SiNx;

Fig. 2 is the sectional view that laminated passivating film is applied to p type crystalline silicon solar cell among the embodiment 2, wherein 21, SiNx; 22, sensitive surface Metal Contact; 23, n+ emitter; 24, first passivating film; 25, second passivating film; 26, shady face Metal Contact;

Fig. 3 is I-V and the P-V test curve that laminated passivating film is applied to p type crystalline silicon solar cell among the embodiment 2;

Fig. 4 be utilize among the embodiment 3 pulse laser at the silicon chip back side laminated passivating film perforate sketch map, wherein 41, Al₂O₃The laminated passivating film of/SiNx.

Embodiment

Embodiment 1

Present embodiment has been explained the utilization (battery sectional view see Fig. 1) of adjustment means on common n type solar cell, and this moment, adjustment means played the effect of passivation and optics anti-reflection simultaneously.Concrete steps are following:

A, choose the lightly doped n type monocrystalline silicon piece of resistivity at 0.1 ~ 10 Ω cm; Be placed in the texturing slot; In weight percentage is 0.5 ~ 5% NaOH deionized water solution, be to carry out surface-texturing under 75 ~ 90 ℃ the condition to form suede structure in temperature;

B, silicon chip surface cleaned adopt chemical solution to clean, chemical solution is a hydrofluoric acid, and concentration is 5-50%, and scavenging period is 0.5 ~ 60 minute, and temperature is 5 ~ 90 ℃;

C, above making herbs into wool sheet cleaned after, place 700 ~ 1000 ℃ boiler tube to carry out boron (B) diffusion preparation p type emitter, be 70-150min diffusion time, diffusion back emitter square resistance is 65-85 Ohm/;

D, above-mentioned silicon chip cleaned carry out phosphorous diffusion in the boiler tube that is placed on 700 ~ 1000 ℃ and prepare the n+ layer, be 50 ~ 100 min diffusion time, and the square resistance that diffusion back phosphorus expands the district is 30 ~ 60 Ohm/;

E, place rinse bath to remove dephosphorization silicon and Pyrex silicon chip after the above-mentioned diffusion;

F, adopt the boron-doping face deposition of aluminium oxide film of ald (ALD) method at above-mentioned clean silicon chip, the reacting gas of employing is Al (CH₃)₃And O₂, thickness is 5 ~ 50 nm;

G, at above-mentioned silicon chip Al₂O₃Utilize plasma reinforced chemical vapour deposition method (PECVD) deposition SiNx deielectric-coating on the deielectric-coating basis, film thickness is controlled between the 50-90 nm, and refractive index is controlled between the 1.9-2.1;

H, utilize the another side of plasma reinforced chemical vapour deposition method at above-mentioned silicon chip, i.e. deposition SiNx passivating film on the phosphorus expansion face, film thickness is controlled between 50 ~ 150 nm, and refractive index is controlled between 1.9 ~ 2.4;

I, backplate printing: on silicon chip phosphorous diffusion face, adopt method for printing screen type metal contact electrode;

J, front electrode printing: the screen-printed metal contact electrode is adopted on the surface that has laminated antireflective film at silicon chip;

K, high temperature Fast Sintering: the silicon chip that prints is placed the sintering furnace sintering, and optimizing sintering temperature is 400 ~ 900 ℃.Silver-colored aluminium (Ag/Al) alloy penetrates aluminium oxide/silicon nitride adjustment means and emitter formation ohmic contact behind sintering, and argent passes the SiNx passivated reflection reducing membrane and is and silicon substrate (base stage) formation ohmic contact.

Utilize aluminium oxide/silicon nitride adjustment means to be used for n type solar cell p+ diffusion layer is carried out surface passivation in the present embodiment, play the effect of anti-reflection simultaneously.Compare with traditional SiNx passivation, recombination-rate surface obviously reduces.Through regulating the thickness and the refractive index of first passivating film and second passivating film, battery surface also can be controlled to lower to reflection of incident light, thereby the output voltage of battery and electric current are also effectively promoted.

Following table 1 adopts aluminium oxide/silicon nitride adjustment means in the present embodiment as the sensitive surface passivated reflection reducing membrane and adopt the photooptical data of SiNx as the sensitive surface passivated reflection reducing membrane for solar cell.

Table 1 p+nn+ solar cell employing adjustment means and common SiNx are as the photooptical data of sensitive surface passivated reflection reducing membrane

Passivating film	Voc(mV)	Jsc(mA.cm-2)	FF(/%)	Eta(%)
					Adjustment means	645.3	38	79	19.4
SiNx	640.2	37.8	78.5	19.0

Data can see that Nx compares with traditional Si from table, adopt the n type solar cell of adjustment means passivation sensitive surface that bigger lifting is all arranged on photoelectric current and photovoltage, and the well passivated effect of this adjustment means has been described.

Embodiment 2

Present embodiment has been explained the utilization (sectional view see Fig. 2) of adjustment means structure on p type silicon solar cell, is mainly used in the passivation to the battery shady face, and concrete steps are following:

A, choose the lightly doped p type monocrystalline silicon piece of resistivity at 0.1 ~ 10 Ω cm; Place texturing slot to carry out affected layer removal and matte preparation the silicon chip matrix; In weight percentage is 0.5 ~ 5% NaOH deionized water solution, be to carry out surface-texturing under 75 ~ 90 ℃ the condition to form suede structure in temperature;

B, silicon chip surface cleaned adopt chemical solution to clean, chemical solution is a hydrofluoric acid, and concentration is 5-50%, and scavenging period is 0.5 ~ 60 minute, and temperature is 5 ~ 90 ℃;

C, place 800 ~ 1000 ℃ boiler tube to carry out phosphorus (P) diffusion silicon chip, form n-type diffusion layer at silicon chip surface.Diffusion back silicon chip square resistance is 65Ohm/;

D, the silicon chip after will spreading place the wet etching groove to remove reverse diffusion layer and phosphorosilicate glass through the method for chemical corrosion;

E, employing ALD method are at above-mentioned silicon chip back deposition of aluminium oxide film, and the reacting gas of employing is AlCl₃And O₂, thickness is 50nm;

F, employing plasma reinforced chemical vapour deposition method are at above-mentioned Al₂O₃Deposition high index of refraction SiC passivating film on the rete, the SiC film thickness is controlled between 10 ~ 100nm, and refractive index is controlled between 0.8 ~ 2.2;

G, employing plasma reinforced chemical vapour deposition method go up deposition SiNx passivated reflection reducing membrane at above-mentioned silicon chip positive (emission pole-face), and film thickness is controlled between 76 ~ 90nm, and refractive index is controlled between the 1.9-2.1;

H, front electrode printing: go up the metal that adopts method for printing screen printing front metal electrode to be adopted at silicon chip phosphorous diffusion face (emission pole-face) and be silver (Ag);

I, backplate printing: method for printing screen type metal back electrode is adopted at the back side that has laminated antireflective film at silicon chip, and the metal that is adopted is silver-colored aluminium (Ag/Al) alloy;

J high temperature Fast Sintering: the silicon chip that prints is placed the sintering furnace sintering, and optimizing sintering temperature is 400-900 ℃.Argent passes SiNx passivated reflection reducing membrane and emitter formation ohmic contact behind sintering, and silver-colored aluminium (Ag/Al) alloy penetrates aluminium oxide/silicon nitride adjustment means and silicon substrate (base stage) forms ohmic contact.

In the present embodiment laminated passivating film is used for the passivation to p type monocrystalline silicon piece shady face; Compare with pure SiNx passivating back; Laminated passivating film has effectively been avoided the appearance of inversion layer after the passivation of SiNx film, has strengthened surface passivation effect, can increase the long-wave band spectral response of battery to sunlight simultaneously; Help impelling the lifting of photovoltage, experimental result is as shown in Figure 3.

Embodiment 3

Present embodiment has explained that the adjustment means structure is used in the making on the p type silicon solar cell, passivation is carried out on battery back of the body surface, and strengthened the reflection of cell backside to unabsorbed sun long wave photon, and then improve the cell photoelectric conversion efficiency.Concrete steps are following:

A, choose the lightly doped p type monocrystalline silicon piece of resistivity at 0.1 ~ 10 Ω cm; Place texturing slot to carry out affected layer removal and matte preparation the silicon chip matrix; In weight percentage is 0.5 ~ 5% NaOH deionized water solution, be to carry out surface-texturing under 75 ~ 90 ℃ the condition to form suede structure in temperature;

B, silicon chip surface cleaned adopt chemical solution to clean, described chemical solution is the mixed solution of hydrofluoric acid and hydrochloric acid, and wherein the ratio of hydrofluoric acid and hydrochloric acid is 1:1, and concentration is 10-50%, and scavenging period is 0.5 ~ 60 minute, and temperature is 5 ~ 90 ℃;

C, with above silicon chip after cleaning, place 800 ~ 1000 ℃ boiler tube to carry out phosphorus (P) diffusion, form n-type diffusion layer at silicon chip surface.Diffusion back silicon chip square resistance is 55 ~ 80 Ohm/;

D, the silicon chip after will spreading place the wet etching groove to remove phosphorosilicate glass and reverse diffusion layer through the method for chemical corrosion;

E, employing MOCVD method are at above-mentioned silicon chip back deposition of aluminium oxide (Al₂O₃) film, the reacting gas of employing is Al (CH3)₂Cl and O₂, thickness is 30-50nm;

F, employing plasma reinforced chemical vapour deposition method deposit high index of refraction SiNx passivating film on above-mentioned aluminium oxide rete, film thickness is controlled between 20 ~ 100nm, and refractive index is controlled between 2.4 ~ 3.0;

G, employing plasma reinforced chemical vapour deposition method go up deposition SiNx passivated reflection reducing membrane at above-mentioned silicon chip positive (emission pole-face), and film thickness is controlled between 76 ~ 90nm, and refractive index is controlled between 1.9 ~ 2.1;

H, adopt the aluminium oxide/silicon nitride laminated passivating film battle shape through hole of short-pulse laser at the silicon chip back side, as shown in Figure 4, the diameter in the hole of opening is 25 ~ 100 μ m; Number is 5000 ~ 50000, and the pulse of used laser can be psec (picosecond), also can be femtosecond; (Femtosecond); Wavelength of Laser can be a ultraviolet, and is visible, or near-infrared;

I, front electrode printing: go up the metal that adopts method for printing screen printing front metal electrode to be adopted at silicon chip phosphorous diffusion face (emission pole-face) and be silver (Ag);

J, backplate printing: method for printing screen type metal back electrode is adopted at the back side that has laminated passivating film at silicon chip, and the metal that is adopted is an aluminium paste.The aluminium paste of silk screen printing covers the whole silicon wafer back side;

K, high temperature Fast Sintering: the silicon chip that prints is placed the sintering furnace sintering, and optimizing sintering temperature is 400 ~ 900 ℃.Argent passes SiNx passivated reflection reducing membrane and emitter formation ohmic contact behind sintering, and the aluminium paste that is adopted forms ohmic contact through point-like through hole and silicon substrate (base stage).

In the present embodiment laminated passivating film is used for the passivation to p type monocrystalline silicon piece shady face; Utilize laser to form the passage of ohmic contact as metal electrode and silicon substrate (base stage) at laminated passivating film shape battle through hole; Not only strengthened surface passivation effect; Do not influence yet and electrically contact, can also increase the long-wave band spectral response of battery simultaneously, the raising of cell photoelectric conversion efficiency is had great benefit sunlight.

Embodiment 4

Present embodiment has been explained individual layer Al₂O₃The utilization of film on p type silicon solar cell is mainly used in the passivation to the battery shady face, and concrete steps are following:

A, choose the lightly doped p type monocrystalline silicon piece of resistivity at 0.1 ~ 3.0 Ω cm; Place texturing slot to carry out affected layer removal and matte preparation the silicon chip matrix; In weight percentage is 0.5 ~ 5% NaOH deionized water solution, be to carry out surface-texturing under 75 ~ 90 ℃ the condition to form suede structure in temperature;

B, silicon chip surface cleaned adopt chemical solution to clean, chemical solution is a hydrofluoric acid aqueous solution, and concentration is 5-50%, and scavenging period is 0.5 ~ 60 minute, and temperature is 5 ~ 90 ℃;

C, place 800 ~ 1000 ℃ boiler tube to carry out phosphorus (P) diffusion silicon chip, form n-type diffusion layer at silicon chip surface.Diffusion back silicon chip square resistance is 60Ohm/;

D, the silicon chip after will spreading place the aqueous solution of hydrofluoric acid and additive to clean and remove phosphorosilicate glass; Used hydrofluoric acid concentration is 5%, the additive that adopts can be the polyether-type silicon surface active agent, concentration is 0.5%; Cleaning temperature is 30-50 ℃, and scavenging period is 3-10 minute;

E, employing plasma reinforced chemical vapour deposition method go up deposition SiNx passivated reflection reducing membrane at above-mentioned silicon chip positive (emission pole-face), and film thickness is controlled between 76 ~ 90nm, and refractive index is controlled between the 1.9-2.1;

F, back side chemical polishing: is to react in 10 ~ 40% the potassium hydroxide aqueous solution silicon chip back in the concentration of heating, and the temperature of heating is 50 ~ 90^oC, through adjustment reaction time control wafer thinning thickness 5 ~ 15 μ m, the rinsing in deionized water of the silicon chip after the polishing is clean, dry for standby;

G, employing plasma reinforced chemical vapour deposition method method are at above-mentioned silicon chip back deposition of aluminium oxide film, and the reacting gas of employing is Al (CH₃)₃And O₂, thickness is 80-120nm, refractive index is 1.5-2.0;

H, front electrode printing: go up the metal that adopts method for printing screen printing front metal electrode to be adopted at silicon chip phosphorous diffusion face (emission pole-face) and be silver (Ag);

I, backplate printing: method for printing screen type metal back electrode is adopted at the back side that has laminated antireflective film at silicon chip, and the metal that is adopted is silver-colored aluminium (Ag/Al) alloy;

J high temperature Fast Sintering: the silicon chip that prints is placed the sintering furnace sintering, and optimizing sintering temperature is 400-900 ℃.Argent passes SiNx passivated reflection reducing membrane and emitter formation ohmic contact behind sintering, and silver-colored aluminium (Ag/Al) alloy penetrates aluminium oxide/silicon nitride adjustment means and silicon substrate (base stage) forms ohmic contact.

In the present embodiment mono-layer oxidized aluminum passivation film is used for the passivation to p type monocrystalline silicon piece shady face, and before deposition, silicon chip surface is carried out special cleaning to strengthen the passivation effect of passivating film to battery surface, use the SiNx passivating back to compare, adopt Al with tradition₂O₃Passivating film has effectively been avoided the appearance of inversion layer after the passivation of SiNx film, helps improving solar cell properties.

Above embodiment only is used to set forth the present invention, and protection scope of the present invention is not only to be confined to above embodiment.Content disclosed by the invention and scope that each parameter is got more than the those of ordinary skill foundation of said technical field all can realize the object of the invention.

Claims (10)

1. dielectric passivation film that is used for solar cell; It is characterized in that: the single layer structure that said dielectric passivation film is made up of first deielectric-coating; Or the layered structure formed by first deielectric-coating and second deielectric-coating of said dielectric passivation film; Wherein first deielectric-coating directly contacts with the silicon substrate material, and second deielectric-coating is deposited on first passivating film.

2. the dielectric passivation film that is used for solar cell according to claim 1 is characterized in that: said first deielectric-coating is the metal oxide with fixed negative charge.

3. the dielectric passivation film that is used for solar cell according to claim 2 is characterized in that: said metal oxide is an aluminium oxide.

4. according to claim 1 or the 2 or 3 described passivating films that are used for solar cell, it is characterized in that: the thickness of said first deielectric-coating is 3-200nm.

5. the dielectric passivation film that is used for solar cell according to claim 1; It is characterized in that: said second deielectric-coating is silicon nitride, carborundum, silica or titanium oxide monofilm, or said second deielectric-coating composite membrane that is two or more composition in silicon nitride, carborundum, silica and the titanium oxide.

6. the dielectric passivation film that is used for solar cell according to claim 5 is characterized in that: the thickness of said second passivating film is 3-200 nm,, refractive index is 0.8-3.0.

7. according to each described dielectric passivation film that is used for solar cell of claim 1; It is characterized in that: said first deielectric-coating and second deielectric-coating comprise that employing ald ALD, chemical vapour deposition (CVD) CVD, PCVD PECVD, metal-organic chemical vapor deposition equipment MOCVD or molecular beam epitaxial growth MBE method prepare; The reacting gas that is adopted when wherein preparing first passivating film comprises a kind of aluminum contained compound at least, and said aluminum contained compound comprises Al (CH3)₃, AlCl₃, Al (CH3)₂Cl or (CH₃)₂C₂H₅N:AlH₃

8. the dielectric passivation film that is used for solar cell according to claim 1 is characterized in that: said dielectric passivation film is arranged at the sensitive surface of solar cell or is arranged at the shady face of solar cell.

9. the dielectric passivation film that is used for solar cell according to claim 1; It is characterized in that: the surface topography of said silicon substrate material is burnishing surface or suede structure; Wherein the burnishing surface structure adopts the chemical solution corrosion to form; Described chemical solution is the KOH or the NaOH aqueous solution, and its quality percentage composition is 10 ~ 40%, and temperature is 50 ~ 90 ℃; Or described chemical solution is TMAH or ethylenediamine solution, and its quality percentage composition is 10 ~ 30%, and temperature is 50 ~ 90 ℃; Wherein said suede structure adopts the chemical solution corrosion to prepare, and said chemical solution is the NaOH aqueous solution, and its quality percentage composition is 0.5 ~ 5%, under 75 ~ 90 ℃ temperature, forms through surface-texturing.

10. the dielectric passivation film that is used for solar cell according to claim 9; It is characterized in that: be on the silicon substrate material of burnishing surface or suede structure before deposition first deielectric-coating at surface topography; The silicon substrate material surface is cleaned; Clean the hydrofluoric acid, nitric acid, hydrochloric acid or the sulfuric acid that adopt hydrofluoric acid, nitric acid, hydrochloric acid or sulfuric acid and contain additive, scavenging period is 0.5-60 minute, and temperature is 5 ~ 90 ℃.

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