CN102851743A

CN102851743A - Method for reducing surface reflectivity during polycrystalline silicon texturing

Info

Publication number: CN102851743A
Application number: CN2012103239369A
Authority: CN
Inventors: 冯晓军
Original assignee: ZHEJIANG FORTUNE PHOTOVOLTAIC CO Ltd
Current assignee: ZHEJIANG FORTUNE PHOTOVOLTAIC CO Ltd
Priority date: 2012-09-05
Filing date: 2012-09-05
Publication date: 2013-01-02
Anticipated expiration: 2032-09-05
Also published as: CN102851743B

Abstract

The present invention discloses a method for reducing surface reflectivity during polycrystalline silicon texturing, and particularly relates to reduction of the surface reflectivity when the surface reflectivity is high during application of polycrystalline silicon to carry out acid texturing. A scheme A comprises that: HNO3 addition is stopped, normal HF addition is ensured, and HNO3 concentration in the solution is reduced after maintaining for a certain time; along with the time lapse, after the reflectivity is reduced to within a required technical parameter range, normal HNO3 addition and normal HF addition are performed. A scheme B comprises that: water is added to reduce the whole concentration of HNO3 and HF, then HF is added, after the reflectivity is reduced to within a required technical parameter range, normal HNO3 addition and normal HF addition are performed. The method of the present invention has the following beneficial effects that: surface reflectivity after polycrystalline silicon texturing can be effectively reduced, bright sheets and color sheets caused by high reflectivity can be reduced, and a purpose of improvement of photoelectric conversion efficiency of the polycrystalline silicon solar cell sheet can be achieved.

Description

A kind of method that reduces polysilicon making herbs into wool surface albedo

Technical field

The present invention relates to the manufacture technology field of crystal silicon solar energy battery, be specifically related to a kind of method that reduces polysilicon making herbs into wool surface albedo in the making herbs into wool operation.

Background technology

In the production technique of crystal silicon solar batteries, silicon chip surface is corroded the surface albedo that the matte of preparing can reduce silicon chip effectively, surface albedo is one of important factor that affects the crystal silicon solar batteries photoelectric transformation efficiency.Because the diversity of polysilicon grain orientation adopts the alkali leather producing process can't obtain uniform matte, therefore can't effectively reduce the surface albedo of polysilicon.At present, in the preparation method of polycrystalline silicon suede, acid corrosion technology (being isotropic etch) can obtain evenly and the lower matte of reflectivity, can realize again the purpose of low cost, large-scale production.

Generally, in actual production process, the ordinary method that reduces silicon wafer wool making rear surface reflectivity is to adopt to promote belt speed or reduce HF and HNO ₃Overall density realize.The method can reduce the silicon chip surface reflectivity, and the silicon slice corrosion amount also descends simultaneously, removes unclean so that cause the silicon chip affected layer.In actual production process, flower sheet, paillette also often can appear.These all can affect the photoelectric transformation efficiency of polysilicon solar battery slice.

Summary of the invention

The purpose of this invention is to provide a kind of method that reduces polysilicon making herbs into wool surface albedo, the method can be in the situation that the attenuate amount be constant, reduce polysilicon making herbs into wool surface albedo, the efficiency of conversion of Effective Raise solar cell can reduce the generation of colored sheet, paillette simultaneously.

The present invention solves that to reduce the technical scheme that the polysilicon surface reflectivity takes as follows:

In the situation that adopt polycrystalline silicic acid to prepare matte, surface albedo appears when too high, and adopt two kinds of technical schemes described below to reduce the reflectivity on polysilicon making herbs into wool surface.Concrete scheme is as follows:

Option A: stop to add HNO ₃, guarantee that HF normally adds, continue after 60 minutes HNO in the solution ₃Density loss, reflectivity reduces; As time goes on, HNO in the solution ₃Density loss, reflectivity further descends; Treat that reflectivity is reduced in the technical parameter claimed range, normally adds HNO ₃And HF.

Option b: add water and reduce HNO ₃With the overall density of HF, and then by adding HF, the concentration that improves HF makes extent of corrosion constant, treats that reflectivity is reduced in the technical parameter claimed range, normally adds HNO ₃And HF.

The invention has the beneficial effects as follows: adopt the surface albedo after technical scheme proposed by the invention can reduce polysilicon making herbs into wool effectively, can effectively reduce the paillette, the pattern sheet that cause because reflectivity is too high, reach the minimizing surface reflection, strengthen photoelectric absorption, thereby reach the purpose of the photoelectric transformation efficiency that improves polysilicon solar battery slice.

Embodiment

The below is according to a kind of method that reduces polysilicon making herbs into wool surface albedo provided by the invention, and the specific embodiments below adopting is described further.The present embodiment is to carry out under the technique of making herbs into wool, diffusion, wax spray, etching, each procedure of the silk screen printing condition identical with former technique.Embodiment is as follows:

1. at HN0 ₃Volume fraction 63%, HF volume fraction 9%, in the solution of pure water volume fraction 28%, temperature is 8 ℃, and etching time is 90 seconds, records polysilicon chip surface albedo 25.5% under this condition, and the attenuate amount is 0.43g.

2. under the condition of step 1, stop to add HNO ₃, guarantee that HF normally adds, continue after 60 minutes, record this moment polysilicon chip surface albedo and drop to 23.2%, again through 10 minutes, record the polysilicon chip surface albedo and drop to 22.6%.

3. treat that reflectivity is reduced to 22.6%, when the attenuate amount keeps 0.43g, normally add HNO ₃And HF.

To place under the standard test condition through the polysilicon solar battery slice of complete processing procedure processing and detect, and take unit for electrical property parameters that technical scheme provided by the invention and former technical scheme carry out the polysilicon solar battery slice that making herbs into wool processes as shown in Table 1 and Table 2.

Table 1 adopts the unit for electrical property parameters of the polysilicon solar battery slice of technical scheme preparation of the present invention

Uoc	Isc	Rs	Rsh	FF	NCell
						0.626	8.56	0.0028	202.99	78.07	17.21%

The unit for electrical property parameters of the polysilicon solar battery slice of the former technical scheme preparation of table 2

Uoc	Isc	Rs	Rsh	FF	NCell
						0.624	8.52	0.0027	186.16	78.15	17.11%

Can find out from above-mentioned experimental result, the polysilicon solar battery slice identical for the attenuate amount, that reflectivity is different, the cell piece efficient that the cell piece efficient that reflectivity is low is higher than reflectivity exceeds 0.1%.This shows, adopt to the invention provides technical scheme, in the situation that guarantee that extent of corrosion is identical, by reducing HNO in the solution ₃Concentration can reach silicon chip with attenuate amount different reflectivity, antiradar reflectivity is conducive to provide the photoelectric transformation efficiency of polysilicon solar battery slice.

Claims

1. method that reduces polysilicon making herbs into wool surface albedo, it is characterized in that: in the situation that adopt polycrystalline silicic acid to prepare matte, when the appearance surface albedo is too high, adopt two kinds of technical schemes described below to reduce the reflectivity on polysilicon making herbs into wool surface, the concrete technology step is as follows: option A: stop to add HNO ₃, guarantee that HF normally adds HNO in the solution after the certain time ₃Density loss, reflectivity reduces, As time goes on, HNO in the solution ₃Density loss, reflectivity further descends, and treats that reflectivity is reduced in the technical parameter claimed range, normally adds HNO ₃And HF; Option b: add water and reduce HNO ₃With the overall density of HF, and then by adding HF, the concentration that improves HF makes extent of corrosion constant, treats that reflectivity is reduced in the technical parameter claimed range, normally adds HNO ₃And HF.