CN102709378A

Movatterモバイル変換

Info

Publication number: CN102709378A
Application number: CN2012100057157A
Authority: CN
Inventors: 黄惠东; 陈永虹; 赖江海; 肖海东
Original assignee: NANAN SANJING SUNSHINE AND POWER Co Ltd
Current assignee: NANAN SANJING SUNSHINE AND POWER Co Ltd
Priority date: 2012-01-09
Filing date: 2012-01-09
Publication date: 2012-10-03

Abstract

The invention relates to a preparation method of a selective emitting electrode crystalline silicon solar battery and belongs to the field of solar batteries. According to the invention, on the basis of previous crystalline silicon solar battery process and equipment, a blocking layer selectively covers a non-electrode region of a battery illuminated face through silk screen printing, film plating and washing treatment, so that a lightly doping region is formed in a diffusion process and a heavily doping region is formed in an electrode region; and then the solar battery is continuously prepared by a common crystalline silicon solar battery production flow. The method disclosed by the invention is simple and efficient, and has a low cost; the defects that the traditional selective emitting electrode crystalline silicon solar battery needs to be subjected to laser treatment or secondary high-temperature diffusion are overcome; and the efficiency of the prepared battery is high and the large-scale industrialization is simple.

Description

A kind of preparation method of selective emitter crystalline silicon solar cell

Technical field

The present invention relates to a kind of preparation method of selective emitter crystalline silicon solar cell.Particularly, through silk screen printing, plated film and clean, make the non-electrode zone selectivity of battery sensitive surface cover barrier layer, make it in diffusion, form light doping section, electrode zone forms heavily doped region.Silicon chip after the diffusion is connected conventional crystal silicon solar energy battery preparation technology again, the preparation crystal silicon solar energy battery.

Background technology

Crystal-silicon solar cell has occupied the most market share of photovoltaic industry, further raises the efficiency, and reducing cost is the elementary object of domestic and international crystal-silicon solar cell research field.Referring to Fig. 1; What the existing conventional crystal-silicon solar cell adopted is the method that is equal to diffusion, and the entire cell sensitive surface adopts same diffusion way, and electrode zone is identical with non-electrode zone thin layer square resistance; Generally at 30-80 Ω; With take into account the electrode contact zone mix can not cross low and sensitive surface mix can not be too high requirement, this compromise doping way can keep low cost, but greatly limits the raising of efficiency of solar cell.

Therefore, the preparation crystal silicon solar cell with selective emitter is significant, and it can be implemented in heavy doping below the battery front surface electrode, and the non-electrode part of front surface (light accepting part branch) light dope.Thereby make the regional diffusion concentration that contacts with metal electrode very high, contact resistance is very little; But not the light area diffusion concentration of electrode is lower, has avoided because the decline of the battery current that the emitter region auger recombination causes, and can effectively improve the performance of crystal-silicon solar cell like this.

There has been the multiple method that can prepare selective emitter solar battery in producer through research for many years both at home and abroad at present.For example; People such as the Zhao Jianhua of CSUN-US, fluting preparation selective emitter battery on the silicon chip behind the hot oxide growth adopts the silicon chip of this technological means must be through twice high temperature; Bigger to the silicon chip self-inflicted injury; The used chemical sizwe of slotting is an ammonium acid fluoride, belongs to highly acid and volatile chemistry, in extensive industrialization, environment and enterprise employee health is had big potential hazard.External Centrotherm company can cause secondary damage to silicon chip equally adopting laser lbg on the silicon chip behind the hot oxide growth, and the laser equipment price is comparatively expensive, and non-most enterprises can accept.Roth&Rau company adopts laser that the light diffusion silicon chip in surperficial phosphors coated source is carried out the secondary diffusion, and its shortcoming is that laser causes the lattice damage of silicon chip surface easily, causes the secondary diffusion zone compound big, the increase rate of restriction electric current.E.I.Du Pont Company has developed silicon ink slurry, adopts screen printing technique to prepare the selective emitter battery, because the silicon ink technology is its exclusive patent at present, secondly, the price of silicon ink is higher.

Summary of the invention

Technical problem to be solved by this invention is, overcomes the technological deficiency of existing selective emitter, and the preparation method of new type of selective emitter crystalline silicon solar cell is provided.

Technical scheme of the present invention is:

A kind of preparation method of selective emitter crystalline silicon solar cell; Electrode zone to the battery sensitive surface carries out the heavy doping diffusion; Non-electrode zone carries out the light dope diffusion, it is characterized in that: before diffusion, utilize silk screen printing, plated film and clean, the battery sensitive surface is carried out optionally barrier layer preparation; Disposable formation electrode district heavy doping in high-temperature diffusion process, non-electrode district light dope.

Particularly, aforesaid preparation method comprises the steps:

A) silicon chip surface texture is handled;

B) battery sensitive surface silk screen printing for the first time, the slurry that will be used for mask covers the zone that the silicon chip light receiving surface need be made electrode;

C) plated film on silicon chip, the clad battery sensitive surface;

D) silicon chip behind the plated film cleans, remove slurry that electrode zone covers and on the film that plates;

E) diffusion: the heavy doping of disposable formation electrode district, non-electrode district light dope;

F) continue to produce etching, cleaning, plating antireflective film, silk screen printing, sintering by conventional manufacture of solar cells technology.

The described mask slurry of step b) wherein, composition can be organic substance, inorganic matter or organic and inorganic mixture, and its demand that can satisfy silk screen printing gets final product.This mask slurry mainly plays a transition role, is printed onto on the silicon chip through screen printing mode, and plated film again, afterwards, this slurry and top plated film are cleaned together to be removed.

Wherein, organic substance includes but not limited to: ethyl cellulose, lecithin, dibutyl phthalate etc.; The high molecular polymerization powder is like epoxy resin, Polyurethane acrylate, epoxy acrylate etc.Inorganic matter includes but not limited to: a kind of or mixture in metal powder (like silver powder), alloyed powder (like the alloy of two or more formation in the metals such as silver-colored zinc, tin, silicon, copper, magnesium, gold, aluminium), glass powder, the metal oxide powder (like transition metal oxide, tin ash, zinc oxide etc.).

Organic and mixture of inorganic substance be for example: the mixture of aforesaid metal powder, glass dust, alloyed powder, metal oxide powder etc. and organic carrier, organic carrier be at least a in ethyl cellulose, terpinol, glycerine, the absolute ethyl alcohol for example; Or polymer and organic solvent mixed dissolution form, and polymer is ethyl cellulose, celluloid, phenolic resins, epoxy resin, polyurethane resin for example, a kind of or mixture in the acrylic resin; A kind of or mixture in solvent such as aforesaid terpinol, turpentine oil, glycerine, absolute ethyl alcohol, propane diols butyl ether, triethyl citrate, ATBC, the lecithin etc.

Wherein the described plated film implementation of step c) can be magnetron sputtering, electron beam evaporation, PECVD, PVD, modes such as sol-gel, spin coating, and the material of plated film comprises α-SiN_x: H, Al₂O₃, SiO₂, amorphous silicon, microcrystal silicon, TiO₂Deng.Coating film thickness can be between 5nm-500um.More preferably, between 100nm-500nm.

Wherein the described cleaning method of step d) adopts and comprises chemical liquid immersion, ultrasonic cleaning etc.; Chemical agent here such as solvent comprise organic solvents such as acetone, ethanol, ethylene glycol, butanediol, polyethylene glycol.It can clean aforesaid slurry and get final product.

Wherein the square resistance of step e) diffusion technology formation comprises two-sided or the single face diffusion at 20-400 Ω;

Wherein the silk screen printing for the second time of step f) battery sensitive surface prepares metallic electrode, makes metallic electrode and step b) mask printed pattern overlapping during printing;

The slurry that the present invention at first adopts the mode of silk screen printing will be used for mask covers the zone that the silicon chip light receiving surface need be made electrode, plated film on silicon chip, clad battery sensitive surface; Silicon chip behind the plated film cleans, and removes the slurry that electrode zone covers.Because mask as thin as a wafer, after the slurry under the mask was cleaned and removes, the mask that is coated on this slurry lost support, also be cleaned and remove, and all the other local masks keeps, thereby form the zone (electrode district) and the masked areas (non-electrode district) of no mask.In diffusion process, mask plays a part partly to stop.The zone of no mask forms heavily diffusion, has the zone of mask to form light diffusion.Thereby non-electrode district diffusion concentration is lower, forms light doping section, side's resistance greatly; Electrode district does not have barrier layer, and diffusion concentration is higher, and formation heavily doped region, side hinder little.During the electrode sintering metal, because the electrode zone diffusion concentration is high, with the ohmic contact resistance that effectively reduces electrode and silicon chip, the fill factor, curve factor of raising battery is prepared the selective emitter solar battery that efficient is higher than common process before silk screen printing.

The present invention adopts the method for silk-screen printing technique and plated film, in the diffusion region of silicon chip surface formation variable concentrations, makes its electrode zone diffusion concentration high; Non-electrode zone concentration is low; Integrated artistic can once spread completion, need not the secondary High temperature diffusion, and is little to the silicon chip damage; Also need not expensive laser equipment, utilize existing conventional equipment can realize significantly to reduce preparation cost, and satisfy extensive common process production technology upgrade requirement.

Description of drawings

Fig. 1 is a production of crystalline silicon solar batteries schematic flow sheet in the prior art; Among the figure, A. removes the silicon chip surface damage, forms deflection surfaces structure and chemical cleaning; B. at POCl₃Spread in the atmosphere; C. clean and remove periphery P N knot; D surface passivation and antireflective coating preparation; The E silk screen printing just, backplate and the back of the body surface field and sintering form ohmic contact.

Fig. 2 is the production procedure sketch map of selective emitter crystalline silicon solar cell of the present invention.Among the figure, A. removes the silicon chip surface damage, forms the deflection surfaces structure; The B silk screen printing intercepts slurry; C. silicon chip film-coated processing; D. cleaning and removing is removed and is intercepted slurry; E. at POCl₃Spread in the atmosphere; F. remove periphery P N knot; G. surface passivation and the deposition antireflection layer; H. silk screen printing just, backplate and the back of the body surface field and sintering form ohmic contact.

Embodiment

Below in conjunction with accompanying drawing and embodiment, the present invention is done further detailed description.

Embodiment 1: as shown in Figure 2, and the preparation method of selective emitter crystalline silicon solar cell.Its technical process is following:

1, carry out chemical cleaning, remove the silicon chip surface damage, formation has the surperficial texture shape of antireflective effect

2, the employing web plate identical with the sensitive surface distribution of electrodes prints slurry to silicon chip, and paste composition contains SiO₂, weight ratio is 40%, all the other 60% for organic bond content are: 20% diethylene glycol, one ether, 20% DPG monomethyl ether, 16% propane diols butyl ether, 3.5% diethyl phthalate, 0.5% ethyl cellulose

3, the silicon chip after step 2 processing is carried out SiO in 250 ℃₂The PECVD plated film, thickness is 250nm

4, the silicon chip after step 3 processing is carried out ultrasonic waves for cleaning 10min in alcohol, in deionized water, carry out ultrasonic waves for cleaning 10min then, dry silicon chip;

5, the silicon chip after step 4 is handled is at POCl₃Middle diffusion, the square resistance in diffusion rear electrode zone is controlled at 40 Ω

6, the silicon chip after step 5 processing is carried out edge etching and clean, used chemical agent is 15% hydrofluoric acid;

7, the silicon chip after step 6 processing is carried out α-SiN_x: the preparation of H antireflective coating;

8, the silicon chip after step 7 processing is carried out silk screen printing positive and negative electrode, sintering metal processing.

Embodiment 2: as shown in Figure 2, and the preparation method of selective emitter crystalline silicon solar cell.Its technical process is following:

1, remove the silicon chip surface damage, formation has the surperficial texture shape of antireflective effect, and carries out chemical cleaning

3, the silicon chip after step 2 processing is carried out Al in the normal temperature vacuum environment₂O₃The PECVD plated film, thickness is 100nm

4, the silicon chip after step 3 processing is carried out ultrasonic waves for cleaning 10min in alcohol, in deionized water, carry out ultrasonic waves for cleaning 10min then, dry silicon chip

5, the silicon chip after step 4 is handled is at POCl₃Middle diffusion, the square resistance in diffusion rear electrode zone is controlled at 55 Ω

6, the silicon chip after step 5 processing is carried out edge etching and clean, used chemical agent is 15% hydrofluoric acid

7, the silicon chip after step 6 processing is carried out α-SiN_x: the preparation of H antireflective coating

Embodiment 3: as shown in Figure 2, and the preparation method of selective emitter crystalline silicon solar cell.Its technical process is following:

2, the employing web plate identical with the sensitive surface distribution of electrodes prints slurry to silicon chip, and paste composition contains SiO₂, concentration is 40%, 60% to be for organic bond content: 20% diethylene glycol, one ether, 20% DPG monomethyl ether, 16% propane diols butyl ether, 3.5% diethyl phthalate, 0.5% ethyl cellulose

3, the silicon chip after step 2 processing is carried out the PECVD plated film of amorphous silicon in 200 ℃, thickness is 250nm

6, the silicon chip after step 5 processing is carried out edge etching and clean, used chemical agent is followed successively by 15% KOH solution and 10%HF solution

Embodiment 4: as shown in Figure 2, and the preparation method of selective emitter crystalline silicon solar cell.Its technical process is following:

2, the employing web plate identical with the sensitive surface distribution of electrodes prints slurry to silicon chip, and slurry contains glass dust 40%-60%, and remainder is an organic bond, and content is: the 5%-10% ethyl cellulose; The 15-20% pine tar; The 20%-30% butanediol.

3, the silicon chip after step 2 processing is carried out the PVD plated film of amorphous silicon in 200 ℃, thickness is 500nm

5, the silicon chip after step 4 is handled is at POCl₃Middle diffusion, the square resistance in diffusion rear electrode zone is controlled at 20 Ω

Embodiment 5:

2, the employing web plate identical with the sensitive surface distribution of electrodes prints slurry to silicon chip; Paste composition contains SiO2; Content is for being 50%, and 50% is organic bond in addition, and concrete content is: 15% diethylene glycol, one ether, 20% DPG monomethyl ether; 11% propane diols butyl ether, 3.5% diethyl phthalate, 0.5% ethyl cellulose

3, the silicon chip after step 2 processing is carried out the PECVD plated film of amorphous silicon in 200 ℃, thickness is 50nm;

5, the silicon chip after step 4 processing is spread in POCl3, the square resistance in diffusion rear electrode zone is controlled at 40 Ω

7, the silicon chip after step 6 processing is carried out α-SiNx:H antireflective coating preparation

Claims

1. the preparation method of a selective emitter crystalline silicon solar cell; Electrode zone to the battery sensitive surface carries out the heavy doping diffusion; Non-electrode zone carries out the light dope diffusion, it is characterized in that: before diffusion, utilize silk screen printing, plated film and clean, the battery sensitive surface is carried out optionally barrier layer preparation; Disposable formation electrode district heavy doping in high-temperature diffusion process, non-electrode district light dope.

2. the preparation method of a kind of selective emitter crystalline silicon solar cell as claimed in claim 1 comprises the steps:

A) silicon chip surface texture is handled;

C) plated film on silicon chip, the clad battery sensitive surface;

F) continue to produce by conventional manufacture of solar cells technology, comprise etching, cleaning, plating antireflective film, silk screen printing, sintering.

3. the preparation method of a kind of selective emitter crystalline silicon solar cell as claimed in claim 2 is characterized in that:

The mask slurry that step b) is used, composition are inorganic matter, organic substance or inorganic organic mixture.

4. the preparation method of a kind of selective emitter crystalline silicon solar cell as claimed in claim 2 is characterized in that:

The implementation of step c) plated film comprises magnetron sputtering, electron beam evaporation, PECVD, PVD, sol-gel, spin-coating method.

5. the preparation method of a kind of selective emitter crystalline silicon solar cell as claimed in claim 2 is characterized in that:

The material of step c) plated film comprises α-SiN_x: H, Al₂O₃, SiO₂, amorphous silicon, microcrystal silicon, TiO₂

6. the preparation method of a kind of selective emitter crystalline silicon solar cell as claimed in claim 2 is characterized in that:

The step c) coating film thickness is between 5nm-500um.

7. the preparation method of a kind of selective emitter crystalline silicon solar cell as claimed in claim 2 is characterized in that: the square resistance that the step e) diffusion technology forms comprises two-sided or the single face diffusion at 20-400 Ω.

8. the preparation method of a kind of selective emitter crystalline silicon solar cell as claimed in claim 2 is characterized in that:

When the silk screen printing for the second time of step f) battery sensitive surface prepares metallic electrode, make metallic electrode and step b) silk screen printing for the first time mask printed pattern overlapping.