CN102569445A

Movatterモバイル変換

Info

Publication number: CN102569445A
Application number: CN2011104615887A
Authority: CN
Inventors: 合田晋二; 鹿野康行; 杉渕康一
Original assignee: PVG SOLUTIONS KK
Current assignee: PVG SOLUTIONS KK
Priority date: 2010-12-22
Filing date: 2011-12-22
Publication date: 2012-07-11
Also published as: JP2012134398A

Abstract

The invention provides a solar cell unit and a method for manufacturing the same. During manufacturing, the high concentration diffusion region is not expanded unnecessarily, even if the light-receiving surface of a grid electrode being offset along the rotation direction, the light-receiving surface of the grid electrode can be aligned with the high-concentration diffusion region. The invention provides a solar battery unit, which comprises a p-type semiconductor substrate; an n-type diffusion layer formed on the light-receiving surface of the semiconductor substrate; and one or more illuminated surface grid electrode locally formed on the n-type diffusion layer.

Description

Solar battery cell and manufacturing approach thereof

Technical field

The present invention relates to solar battery cell and manufacturing approach thereof.

Background technology

Solar battery cell is the semiconductor element that transform light energy is become electric power, has p-n junction type, pin type, Schottky type etc., and the p-n junction type especially is widely used.In addition, if solar cell is classified based on its baseplate material, then roughly be divided into 3 kinds of silicon crystal class solar cell, amorphous (noncrystalline) silicon class solar cell, compound semiconductor class solar cell.Silicon crystal class solar cell further is classified into monocrystalline class solar cell and polycrystalline class solar cell.Because the silicon for solar cell crystal substrate can be made with comparalive ease, thereby silicon crystal class solar cell is the most universal.

Solar cell as clean energy resource and in recent years demand is improving, and what accompany therewith is that the demand of solar battery cell is also improving.In addition, from the viewpoint of energy efficiency, expect the high as much as possible to the conversion efficiency of electric power of solar battery cell from luminous energy.

In order to improve from the conversion efficiency of luminous energy to electric power, for example, inpatent documentation 1; The solar cell and the manufacturing approach thereof of following structure are disclosed: as shown in Figure 1; At diffusion layer the high-concentration diffusion region territory is set,, widens the width in high-concentration diffusion region territory in order to carry out of the printing of sensitive surface gate electrode reliably to the high-concentration diffusion region territory; Even the aligning at the sensitive surface gate electrode produces under the situation of skew, the sensitive surface gate electrode can not touch the low-concentration diffusion region territory yet.

Patent documentation 1: TOHKEMY 2010-118473 communique

Yet; In the invention that above-mentionedpatent documentation 1 is put down in writing; Under the skew of the aligning of sensitive surface gate electrode becomes big situation; Only be necessary to deal with, in solar battery cell,, the decline of the electric current that is short-circuited (Jsc) arranged and the worry that can not seek the raising of conversion efficiency under the excessive condition of enlarged in high-concentration diffusion region territory through enlarging the high-concentration diffusion region territory.As shown in Figure 2 in addition,, being aligned in of sensitive surface gate electrode, have the sensitive surface gate electrode to come off and the worry of touching the low-concentration diffusion region territory when overlooking from the high-concentration diffusion region territory along under the situation of direction of rotation skew.

Summary of the invention

In view of the foregoing; The objective of the invention is to; Following solar battery cell and manufacturing approach thereof is provided: during fabrication; The high-concentration diffusion region territory is surpassed necessarily enlarges, though at the aligning of sensitive surface gate electrode along under the situation of direction of rotation skew, also can precision well with the sensitive surface gate electrode to being positioned on the high-concentration diffusion region territory.

In order to reach above-mentioned purpose, according to the present invention, a kind of solar battery cell is provided, comprising: p N-type semiconductor N substrate; The n type diffusion layer that forms in the sensitive surface side of said semiconductor substrate; And one or more sensitive surface gate electrodes that form partly at said n type diffusion layer; Wherein, At said n type diffusion layer, be formed with a plurality of high-concentration diffusion region territory and the low-concentration diffusion region territory between these high-concentration diffusion region territories, the width in said high-concentration diffusion region territory constitutes when overlooking both ends and compares broad with central part; Said sensitive surface gate electrode is formed at said high-concentration diffusion region territory, and the distance between centers in the said high-concentration diffusion region territory of adjacency is 1.5～3.0mm.

In addition,, a kind of solar battery cell is provided, comprises: n N-type semiconductor N substrate according to the present invention; The p type diffusion layer that forms in the sensitive surface side of said semiconductor substrate; And one or more sensitive surface gate electrodes that form partly at said p type diffusion layer; Wherein, At said p type diffusion layer, be formed with a plurality of high-concentration diffusion region territory and the low-concentration diffusion region territory between these high-concentration diffusion region territories, the width in said high-concentration diffusion region territory constitutes when overlooking both ends and compares broad with central part; Said sensitive surface gate electrode is formed at said high-concentration diffusion region territory, and the distance between centers in the said high-concentration diffusion region territory of adjacency is 1.5～3.0mm.

The width A of the central part during the overlooking of said high-concentration diffusion region territory also can constitute narrower than the width B at both ends, and the difference of the length of the width A of said central part and the width B at said both ends also can be in the 0.5mm.

The sheet resistance in said high-concentration diffusion region territory also can be 25～55 Ω/, and the sheet resistance in said low-concentration diffusion region territory also can be 60～150 Ω/.In addition, said semiconductor substrate also can be monocrystalline silicon or polysilicon, and it also can be 0.3～50 Ω cm than resistance (resistivity).

In addition, according to the present invention from another viewpoint, a kind of manufacturing approach of solar battery cell is provided, this method possesses: the operation that as mask said dielectric film is etched into set pattern with the etchant resist of the coating of the dielectric film on semiconductor substrate; Said dielectric film to form set pattern makes the exposed portions serve of said semiconductor substrate become the operation in high-concentration diffusion region territory as mask; Removing the said dielectric film that forms set pattern makes the rest parts of said semiconductor substrate become the operation in low-concentration diffusion region territory; And the operation that on said high-concentration diffusion region territory, forms the electrode that constitutes by conductive paste through silk screen printing, the width in said high-concentration diffusion region territory constitutes when overlooking both ends and compares broad with central part.

In addition, according to the present invention, a kind of manufacturing approach of solar battery cell is provided, this method possesses: in whole operation that forms the low-concentration diffusion region territory of the sensitive surface of semiconductor substrate; Form the operation in high-concentration diffusion region territory through the heat treatment that keeps phosphate glass in the part that should be made as the high-concentration diffusion region territory and append; And the operation that on said high-concentration diffusion region territory, forms the electrode that constitutes by conductive paste through silk screen printing, the width in said high-concentration diffusion region territory constitutes when overlooking both ends and compares broad with central part.

In addition, according to the present invention, a kind of manufacturing approach of solar battery cell is provided, this method possesses: in whole operation that forms the high-concentration diffusion region territory of the sensitive surface of semiconductor substrate; Thereby form etchant resist as mask and form the operation in low-concentration diffusion region territory through the part of exposing being carried out etching in the part that should be made as the high-concentration diffusion region territory; And the operation that on said high-concentration diffusion region territory, forms the electrode that constitutes by conductive paste through silk screen printing, the width in said high-concentration diffusion region territory constitutes when overlooking both ends and compares broad with central part.

In addition, according to the present invention, a kind of manufacturing approach of solar battery cell is provided, this method possesses: the operation that forms dielectric film at semiconductor substrate; Dielectric film is etched into the operation of set pattern as mask to be formed at etchant resist on the dielectric film; Removing etchant resist makes the exposed portions serve of semiconductor substrate become that the high-concentration diffusion region territory simultaneously connects dielectric film as the diffuse elements of diffuse source and the operation that forms the low-concentration diffusion region territory; And the operation that on said high-concentration diffusion region territory, forms the electrode that constitutes by conductive paste through silk screen printing, the width in said high-concentration diffusion region territory constitutes when overlooking both ends and compares broad with central part.

The sheet resistance in said high-concentration diffusion region territory also can be 25～55 Ω/, and the sheet resistance in said low-concentration diffusion region territory also can be 60～150 Ω/.In addition, said semiconductor substrate also can be monocrystalline silicon or polysilicon, and it also can be 0.3～50 Ω cm than resistance.

Can be etchant resist also through the mask that silk screen printing is formed for forming said high-concentration diffusion region territory and/or said low-concentration diffusion region territory.The situation and the alignment methods that forms the situation of said electrode that are formed for forming the etchant resist in said high-concentration diffusion region territory also can be identical methods.In this case; Be formed for forming the method that the alignment methods of situation and the situation that forms said electrode of the etchant resist in said high-concentration diffusion region territory also can be to use each 2 limit at the diagonal angle that forms semiconductor substrate to carry out, the situation and the alignment methods of the situation that forms said electrode that are formed for forming the etchant resist in said high-concentration diffusion region territory also can be the methods of carrying out through the center of detecting semiconductor substrate.

In addition, as the resist of the formation that is used for said etchant resist, also can use the resist that can print, have anti-HF (hydrofluoric acid) property through silk screen print method, can utilize alkaline aqueous solution to peel off.

According to the present invention; Such solar battery cell and manufacturing approach thereof is provided: during fabrication; The high-concentration diffusion region territory is surpassed necessarily to be enlarged; Even at the aligning of sensitive surface gate electrode along under the situation of direction of rotation skew, also can precision well with the sensitive surface gate electrode to being positioned on the high-concentration diffusion region territory.

Description of drawings

Fig. 1 is high-concentration diffusion region territory and the key diagram of sensitive surface gate electrode that illustrates in the existing solar battery cell.

Fig. 2 is the key diagram the when misregistration of the sensitive surface gate electrode in the existing solar battery cell is shown.

Fig. 3 is the key diagram of the manufacturing process of the present invention's solar battery cell of implementing to relate to.

Fig. 4 is the high-concentration diffusion region territory that the forms set pattern diagrammatic illustration figure when overlooking.

Fig. 5 is the key diagram when the high-concentration diffusion region territory is clathrate and is formed at overlooking of situation on the substrate.

Fig. 6 is performance and the chart of the performance of the solar battery cell that the present invention relates to of the solar battery cell of relatively existing type.

Description of reference numerals

1 semiconductor substrate; 2 oxide-films; 3 etchant resists; 4 clearance portion; 5 high-concentration diffusion region territories; 6 low-concentration diffusion region territories; 7 sensitive surface gate electrodes; 8 antireflection films; 9 backplates; 10AL-BSF; 20 solar battery cells; The L distance between centers; The M width.

Embodiment

Below, with reference to accompanying drawing, execution mode of the present invention is described.Fig. 3 (a)～(i) is to use thesemiconductor substrate 1 that is made up of monocrystalline silicon substrate to make the key diagram of the operation of solar battery cell 20.In addition, in this specification and accompanying drawing, through the identical symbol of inscape mark of identical functions formation omits repeat specification to having in fact.

At first; Shown in Fig. 3 (a); Prepare thesemiconductor substrate 1 of p type (boron dopings), thissemiconductor substrate 1 is 30～500 μ m, is 0.5～50 Ω cm (concentration ofdopant 4 * 10 than resistance by, thickness square through crystal face orientation (100), the 12.5cm of for example CZ method making¹⁵～5 * 10¹⁶Cm^-3Degree) monocrystalline silicon substrate constitutes.

Then, make silicon substrate impregnated in the sodium hydrate aqueous solution of high concentration (10wt%), remove affected layer.In addition,, use sodium hydrate aqueous solution, but also can use strong alkali aqueous solutions such as potassium hydroxide for the affected layer of removingsemiconductor substrate 1 at this.In addition, even the aqueous acid of fluorine nitric acid (Off Star nitric acid) etc. also can be reached same purpose.

Solar cell preferably forms concaveconvex shape usually on the surface.Its reason is because for the reflectivity that makes the visible region reduces, be necessary to carry out the reflection more than 2 times as far as possible at sensitive surface.So the substrate immersion through will carrying out damnification etching carries out wet etching to this substrate, thereby forms the random grain structure in for example isopropyl alcohol being added into the aqueous solution that the NaOH of 3wt% forms.These protruding one by one sizes are 1～20 μ m degree.As other representational concave-convex surface structures, can enumerate out V groove, U groove.Can utilize grinder to form these structures.In addition, for the sag and swell of Making of Random, instead method can be used acid etching or reactive ion etching etc.

Then, shown in Fig. 3 (b), in containing the atmosphere of aerobic,, form oxide-film 2 on the surface ofsemiconductor substrate 1 through 980 ℃ heat treated.In addition, also can form nitride film and replace oxide-film.

Then, shown in Fig. 3 (c),etchant resist 3 is coated on the oxide-film 2 with the for example thickness of 10～30 μ m with set pattern.In this case; Etchantresist 3 is carried out pattern to be formed; Thereby about theclearance portion 4 that is formed on etchant resist 3, theclearance portion 4 of adjacency distance between centers L each other becomes 1.5～3.0mm, and the width M of eachclearance portion 4 becomes 20%～60% the size of distance between centers L.The pattern of etchant resist 3 forms and carries out through for example silk screen printing.In addition, the resist that applies asetchant resist 3 can use the resist that can print, have anti-HF (hydrofluoric acid) property through silk screen print method, can utilize alkaline aqueous solution to peel off.

Then, shown in Fig. 3 (d), as mask, use the for example Wet-type etching of the 10%HF aqueous solution, oxide-film 2 is etched into set pattern with etchant resist 3.In this case, oxide-film 2 is etched into the pattern same with the clearance portion that forms at etchant resist 34.

Then, shown in Fig. 3 (e), remove etchant resist 3.In this case, peel off etchant resist 3 by alkaline aqueous solution.

Then, in diffusion furnace, containing phosphorus oxychloride (POCl₃) be heated to 870 ℃ in the atmosphere of gas, thus, shown in Fig. 3 (f), as mask, phosphorus (P) is diffused to the exposed portions serve ofsemiconductor substrate 1 with the oxide-film 2 that is etched into set pattern.Like this, a plurality of high-concentrationdiffusion region territory 5 is the surface that island is formed at semiconductor substrate 1.In this case, the sheet resistance in high-concentrationdiffusion region territory 5 becomes 25～55 Ω/ (ohms/square: ohm/square).In addition, high-concentrationdiffusion region territory 5 distance between centers L each other adjacent to each other becomes 1.5～3.0mm.

Fig. 4 is the diagrammatic illustration figure when forming the overlooking of high-concentrationdiffusion region territory 5 of set pattern.At this, in order to explain, also diagram has following illustrated sensitive surface gate electrode 7 in Fig. 4.As shown in Figure 4, the width in high-concentrationdiffusion region territory 5 constitutes when overlooking both ends and compares broad with central part.That is, high-concentrationdiffusion region territory 5 has so-called bow tie shape, and the width A of central part constitutes narrower than the width B at both ends.At this, the difference of the length of the width A of central part and the width B at both ends is in the 0.5mm.

Making the difference of length of width B at width A and the both ends of central part is in the 0.5mm; Be because the main flow of the specification of solar cell silicon substrate is overall dimension ± 0.5mm usually; Even for deviation is tolerance substrate to greatest extent; So long as the structure of the solar battery cell that this execution mode relates to just can form and select the diffusion structure.

Then, shown in Fig. 3 (g), use the for example Wet-type etching of the 10%HF aqueous solution, remove oxide-film 2.

Then, in diffusion furnace, containing phosphorus oxychloride (POCl₃) be heated to 830 ℃ in the atmosphere of gas, thus, shown in Fig. 3 (h), the surface that phosphorus (P) is diffused tosemiconductor substrate 1 is whole.Like this, on the surface ofsemiconductor substrate 1, be formed with low-concentrationdiffusion region territory 6 each other in a plurality of high-concentration diffusion region territory 5.In this case, the sheet resistance in low-concentrationdiffusion region territory 6 becomes 60～150 Ω/.

Then; The PN junction that utilizes plasma etcher to carry out the semiconductor substrate periphery separates; Then, utilize hydrofluoric acid aqueous solution to remove to be formed at the phosphate glass of substrate surface, then; Use plasma CVD equipment, for example on emitter layer, pile up nitride film as surface protection film (passivating film) antireflection film 8 of holding concurrently.As other antireflection films 8, there are oxide-film, titanium dioxide film, Zinc oxide film, tin oxide film etc., can replace.In addition, the formation method also exists remote control (remote) plasma CVD method, coating process, vacuum vapour deposition etc. except above-mentioned, but from economic viewpoint, it is best forming nitride film through plasma CVD method as stated.And to become minimum such condition, this refractive index of for example bifluoride magnesium film be the film between 1 to 2 if on above-mentioned antireflection film 8, form total reflectivity, and then reflectivity further reduces, and generates current density and uprises.

Then, shown in Fig. 3 (i), use screen process press that backplate 9 is printed on the substrate back side and makes backplate 9 dryings.For example, invest the substrate back side and form backplate 9 through utilizing silk screen printing that the conductive paste that contains Ag is coated with.Subsequently, will be coated on the part except that backplate 9 of substrate back side by the cream that aluminium etc. constitutes and make this cream dry.

And, on each high-concentrationdiffusion region territory 5, form sensitive surface gate electrode 7.For example, form sensitive surface gate electrode 7 through utilizing silk screen printing that the conductive paste that contains Ag is coated on each high-concentration diffusion region territory 5.Subsequently, burn till, make sensitive surface gate electrode 7 and backplate 9 sintering, make AL-BSF 10 be formed at the part except that backplate 9,solar battery cell 20 is able to make.

In the solar battery cell of making through the operation ofabove explanation 20, the shape in high-concentrationdiffusion region territory 5 is constituted when overlooking both ends compare broad with central part.That is, high-concentrationdiffusion region territory 5 has so-called bow tie shape, and the width A of central part constitutes narrower than the width B at both ends.Thus; Even the aligning (contraposition) of sensitive surface gate electrode 7 that becomes problem in the prior art is along under the situation of direction of rotation skew; The contraposition of sensitive surface gate electrode 7 also becomes easily, can be with sensitive surface gate electrode 7 precision well to being positioned on the high-concentrationdiffusion region territory 5.

More than, an example of execution mode of the present invention has been described, but the present invention is not limited to illustrated mode.Can understand: obviously,,, also belong to technical scope of the present invention certainly this so long as the person of ordinary skill in the field just can expect various change examples or correction example in the category of the thought that the scope of claim is put down in writing.

For example; In the above-described embodiment, as shown in Figure 4, enumerate and explained high-concentrationdiffusion region territory 5 is the structure that island is arranged in parallel; But the invention is not restricted to this, the direction that high-concentrationdiffusion region territory 5 is revolved in the substrate upper edge turn 90 degrees forms (being so-called clathrate forms).Fig. 5 is the key diagram when high-concentrationdiffusion region territory 5 is clathrate and is formed at overlooking of situation on the substrate.As shown in Figure 5; Form through high-concentrationdiffusion region territory 5 being clathrate; Thereby be under the situation more than the tolerance of contour substrate size at alignment offset,, thereby also can keep the performance ofsolar battery cell 20 because the high-concentrationdiffusion region territory 5 of longitudinal direction contacts with sensitive surface gate electrode 7.

Embodiment

As embodiments of the invention, measure the performance of solar battery cell that prior art shown in Figure 2 relates to and the solar battery cell that the present invention relates to shown in Figure 4 respectively.Fig. 6 is performance and the chart of the performance of the solar battery cell that the present invention relates to of the solar battery cell of relatively existing type.As shown in Figure 6, can know that the solar battery cell that the present invention relates to is no matter its position how, all is stable and high performance.

Utilizability on the industry

The present invention can be applicable to solar battery cell and manufacturing approach thereof.

Claims

1. solar battery cell comprises:

P N-type semiconductor N substrate;

The n type diffusion layer that forms in the sensitive surface side of said semiconductor substrate; And

One or more sensitive surface gate electrodes that form partly at said n type diffusion layer, wherein,

At said n type diffusion layer, be formed with a plurality of high-concentration diffusion region territory and the low-concentration diffusion region territory between these high-concentration diffusion region territories,

The width in said high-concentration diffusion region territory constitutes when overlooking both ends and compares broad with central part,

Said sensitive surface gate electrode is formed at said high-concentration diffusion region territory,

The distance between centers in the said high-concentration diffusion region territory of adjacency is 1.5～3.0mm.

2. solar battery cell comprises:

N N-type semiconductor N substrate;

The p type diffusion layer that forms in the sensitive surface side of said semiconductor substrate; And

One or more sensitive surface gate electrodes that form partly at said p type diffusion layer, wherein,

At said p type diffusion layer, be formed with a plurality of high-concentration diffusion region territory and the low-concentration diffusion region territory between these high-concentration diffusion region territories,

3. according to claim 1 or claim 2 solar battery cell, wherein,

The width A of the central part during the overlooking of said high-concentration diffusion region territory constitutes narrower than the width B at both ends, and the difference of the length of the width A of said central part and the width B at said both ends is in the 0.5mm.

4. according to claim 1 or claim 2 solar battery cell, wherein,

The sheet resistance in said high-concentration diffusion region territory is 25～55 Ω/.

5. according to claim 1 or claim 2 solar battery cell, wherein,

The sheet resistance in said low-concentration diffusion region territory is 60～150 Ω/.

6. according to claim 1 or claim 2 solar battery cell, wherein,

Said semiconductor substrate is monocrystalline silicon or polysilicon, and it is 0.3～50 Ω cm than resistance.

7. the manufacturing approach of a solar battery cell possesses:

As mask said dielectric film is etched into the operation of set pattern with the etchant resist of the coating of the dielectric film on semiconductor substrate;

Said dielectric film to form set pattern makes the exposed portions serve of said semiconductor substrate become the operation in high-concentration diffusion region territory as mask;

Removing the said dielectric film that forms set pattern makes the rest parts of said semiconductor substrate become the operation in low-concentration diffusion region territory; And

On said high-concentration diffusion region territory, form the operation of the electrode that constitutes by conductive paste through silk screen printing,

The width in said high-concentration diffusion region territory constitutes when overlooking both ends and compares broad with central part.

8. the manufacturing approach of a solar battery cell possesses:

In whole operation that forms the low-concentration diffusion region territory of the sensitive surface of semiconductor substrate;

Form the operation in high-concentration diffusion region territory through the heat treatment that keeps phosphate glass in the part that should be made as the high-concentration diffusion region territory and append; And

9. the manufacturing approach of a solar battery cell possesses:

In whole operation that forms the high-concentration diffusion region territory of the sensitive surface of semiconductor substrate;

Form etchant resist in the part that should be made as the high-concentration diffusion region territory as mask, thereby through the part of exposing being carried out the operation in etching formation low-concentration diffusion region territory; And

10. the manufacturing approach of a solar battery cell possesses:

Form the operation of dielectric film at semiconductor substrate;

Dielectric film is etched into the operation of set pattern as mask to be formed at etchant resist on the dielectric film;

Remove etchant resist and make the exposed portions serve of semiconductor substrate become that the high-concentration diffusion region territory connects dielectric film as the diffuse elements of diffuse source simultaneously and the operation that forms the low-concentration diffusion region territory; And

11. like the manufacturing approach of each the described solar battery cell in the claim 7～10, wherein,

12. like the manufacturing approach of each the described solar battery cell in the claim 7～10, wherein,

13. like the manufacturing approach of each the described solar battery cell in the claim 7～10, wherein,

14. like the manufacturing approach of claim 7,9, each described solar battery cell of 10, wherein,

Form as the etchant resist that is used to form the mask in said high-concentration diffusion region territory and/or said low-concentration diffusion region territory through silk screen printing.

15. the manufacturing approach of solar battery cell as claimed in claim 14, wherein,

The situation and the alignment methods that forms the situation of said electrode that are formed for forming the etchant resist in said high-concentration diffusion region territory are identical methods.

16. the manufacturing approach of solar battery cell as claimed in claim 14, wherein,

Be formed for forming the method that the alignment methods of situation and the situation that forms said electrode of the etchant resist in said high-concentration diffusion region territory is to use each 2 limit at the diagonal angle that forms semiconductor substrate to carry out.

17. the manufacturing approach of solar battery cell as claimed in claim 14, wherein,

The situation and the alignment methods of the situation that forms said electrode that are formed for forming the etchant resist in said high-concentration diffusion region territory are the methods of carrying out through the center of detecting semiconductor substrate.

18. like the manufacturing approach of claim 7,9, each described solar battery cell of 10, wherein,

As the resist of the formation that is used for said etchant resist, the resist that use can be printed, have anti-HF (hydrofluoric acid) property through silk screen print method, can be utilized alkaline aqueous solution to peel off.