CN104009116A - Manufacturing method of diamond line cutting polycrystalline silicon wafer battery - Google Patents

Abstract

The invention discloses a method for making a diamond wire-cut polycrystalline silicon wafer battery, which belongs to the technical field of solar cells and comprises the following steps: 1) pre-cleaning a P-type polycrystalline silicon wafer to remove a damaged layer to obtain a silicon wafer after removing the damaged layer; 2) Place the damaged silicon wafer in the reaction chamber of the texturing device for dry texturing; 3) Difuse the phosphorus source on the surface of the silicon wafer after dry texturing to obtain a silicon wafer after the phosphorus source has been diffused; 4) Put the phosphorus source The diffused silicon wafer is subjected to wet etching, and then PECVD deposits SiNx film on the front surface to obtain the deposited silicon wafer; 5) Print silver paste and aluminum paste on the back of the deposited silicon wafer, then dry them, and then The positive surface is printed with positive silver and then sintered to obtain a finished battery. The manufacturing method improves the short-wave response, improves the conversion efficiency of solar cells, has wide application range, good cell morphology and effect, and high solar conversion efficiency.

Description

Manufacturing method of diamond wire cut polysilicon wafer cell

technical field

The invention belongs to the technical field of solar cells, and in particular relates to a cell manufacturing method for diamond wire cutting polycrystalline silicon wafers. the

Background technique

Diamond wire cutting technology is also called bonded abrasive cutting technology. It uses electroplating or resin bonding to attach diamond abrasives to the surface of steel wires, and directly acts on the surface of silicon rods or silicon ingots to produce grinding. Compared with the conventional mortar cutting technology, diamond wire cutting has the characteristics of fast speed, high production capacity, high cutting precision and low material loss, but the silicon wafer surface has obvious line marks and the crack density of silicon wafer is very low. , the subsequent battery manufacturing process needs to be improved or combined with other methods. the

The diamond wire-cut battery adopts conventional texturing technology, the surface of the silicon wafer is relatively bright, and the reflectance after texturing is greater than 30%. If silver nitrate or gold trichloride is used for cleaning with metal catalysis, the reflectance of the battery is reduced, but The uniformity of the silicon surface will be affected, resulting in a serious color difference in the appearance of the cell surface, and the removal of metal ions may be incomplete, which will affect the quality and life of the solar cell and the diffusion furnace tube. Optical loss is one of the important obstacles to improving the efficiency of solar cells. To reduce the light reflection on the surface of solar cells, anti-reflection coatings and anti-reflection structures can be used. Conventional texturing, silver nitrate cleaning, gold trichloride cleaning and other technologies are no longer possible. Meet the battery technology production requirements of diamond wire cutting silicon wafers. the

Contents of the invention

Purpose of the invention: The purpose of the present invention is to provide a method for manufacturing a diamond wire-cut polycrystalline silicon wafer cell. The method has good process stability, can ensure high quality of the cell, has good cell shape and effect, and has high solar conversion efficiency. the

Technical solution: In order to achieve the above-mentioned purpose of the invention, the present invention adopts the following technical solutions:

The manufacturing method of the cell of diamond wire cut polysilicon wafer, comprises the steps:

1) Pre-cleaning the P-type polysilicon wafer, removing the damaged layer with a mixed solution of HNO ₃ and HF on the surface to obtain a silicon wafer after removing the damaged layer;

2) Place the damaged silicon wafer in the reaction chamber of the texturing device, and feed gas _SF6 and _O2 to carry out dry texturing for 10 minutes to obtain the silicon wafer after dry texturing;

3) Diffusion of phosphorus source on the surface of silicon wafer after dry texturing, using POCl ₃ liquid phosphorus diffusion source to prepare PN junction, diffusion temperature of 830°C, time of 80min, sheet resistance of 60-90ohm, obtained silicon after phosphorus source diffusion piece;

4) Wet-etching the silicon wafer after the phosphorus source has been diffused, and then depositing a SiNx film on its front surface by PECVD to obtain a deposited silicon wafer;

5) Printing silver paste and aluminum paste on the back of the deposited silicon wafer, drying them, and then printing front silver on the front surface and sintering to obtain a finished battery. the

In step 1), the thickness of the removed damaged layer is 2.5-4 μm. the

In step 2), the reflectance of the silicon wafer after RIE dry texturing is 5-15%. the

In step 4), the thickness of the SiNx anti-reflection film is controlled at 70-90 nm, the reflectivity is 0.5%-3%, and the refractive index is 1.9-2.3. the

The resistivity of the P-type polysilicon sheet is 1-3Ω·cm. the

A cell using the diamond wire cut polysilicon wafer prepared by the above method. the

Invention principle: after removing the damaged layer on the surface, use reactive ion etching RIE texturing technology to obtain ideal textured structure and produce solar cells with low reflectivity, improve short-wave response, and improve solar cell conversion efficiency; while traditional methods use silver nitrate or Metal catalysis such as gold trichloride is used for cleaning, although the reflectance of the battery is reduced (reflectance > 10%), but the uniformity of the silicon surface is affected, resulting in serious appearance and color difference on the surface of the battery, and it is possible to remove metal ions Incomplete, affecting the quality and life of solar cells. the

Beneficial effects: the manufacturing method of diamond wire-cut polysilicon wafer battery of the present invention has simple process and good stability. By first removing the damage and then using reactive ion etching RIE texturing technology, an ideal textured structure and low reflectivity can be obtained. The solar cell can improve the short-wave response, improve the conversion efficiency of the solar cell, and has a wide range of applications. It is not only suitable for the cell production of diamond wire cut silicon wafers, but also suitable for subsequent cell production of silicon wafers with other cutting methods. The shape of the cell is good. Solar energy High conversion efficiency and good practicability. the

Description of drawings

Fig. 1 is a schematic diagram of the structure of a diamond wire-cut polysilicon wafer cell. the

specific embodiment

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. the

As shown in Figure 1, the structure of the diamond wire-cut polycrystalline silicon wafer cell is based on a P-type diamond wire-cut polycrystalline silicon wafer. After the silicon wafer is pre-cleaned, the surface is treated to remove the damaged layer, and the reactive ion etching (RIE) technology is used to fabricate. After the texturing is completed, the phosphorus source is diffused on the front surface to prepare a P-N junction, and an N+ emitter is formed on the surface. After wet etching, a layer of SiNx anti-reflection film is deposited on the front surface by PECVD, and silver paste is printed on the back of the battery. , aluminum paste, drying, and then sintering after printing positive silver on the front surface to obtain a finished battery. the

PECVD, Plasma Enhanced Chemical Vapor Deposition, it uses microwave or radio frequency to ionize the gas containing the constituent atoms of the film to form plasma locally, and the plasma is chemically active and easy to react, depositing the desired material on the substrate. In order to enable the chemical reaction to proceed at a lower temperature, the activity of the plasma is used to promote the reaction. the

RIE, the full name is Reactive Ion Etching, reactive ion etching, a microelectronic dry etching process, it is a kind of dry etching, the principle of this etching is that when a high frequency of 10-100MHZ is applied between the plate electrodes When the voltage is applied, an ion layer with a thickness of hundreds of microns will be generated, and the sample is placed in it, and the ion hits the sample at high speed to complete the chemical reaction etching. the

Example 1

Using the P-type polycrystalline silicon chip with a resistivity of 1 Ω cm as a diamond wire-cut silicon chip, the method for making a battery of a diamond wire-cut polycrystalline silicon chip includes the following steps:

1) Pre-clean the P-type polycrystalline silicon wafer, remove the damaged layer with a thickness of 3.5 μm with a mixed solution of HNO ₃ and HF on the surface, and obtain the silicon wafer after removing the damaged layer;

2) Place the damaged silicon wafer in the reaction chamber of the texturing device, and feed gas SF ₆ and O ₂ to carry out dry texturing for 10 minutes. film, the dry texturing here is the RIE technology;

3) Diffusion of phosphorus source on the surface of silicon wafer after dry texturing, using POCl ₃ liquid phosphorus diffusion source to prepare PN junction, diffusion temperature of 830°C, time of 80min, square resistance of 80ohm, to obtain silicon wafer after phosphorus source diffusion;

4) wet-etching the silicon wafer after the phosphorus source is diffused, and then PECVD-depositing a SiNx anti-reflection film on its front surface with a thickness of 80nm, a reflectivity of 1.3%, and a SiNx film with a refractive index of 2.05 to obtain the deposited silicon piece;

5) Printing silver paste and aluminum paste on the back of the deposited silicon wafer, drying them, and then printing front silver on the front surface and sintering to obtain a finished battery. the

Example 2

Using the P-type polycrystalline silicon chip with a resistivity of 2 Ω cm as a diamond wire-cut silicon chip, the method for making a battery of a diamond wire-cut polycrystalline silicon chip includes the following steps:

1) Pre-clean the P-type polysilicon wafer, remove the damaged layer with a mixed solution of _HNO3 and HF on the surface, the thickness is 2.5 μm, and obtain the silicon wafer after removing the damaged layer;

2) Place the damaged silicon wafer in the reaction chamber of the texturing device, and feed gas SF ₆ and O ₂ for dry texturing. The time is 10 minutes, and the reflectivity after texturing is 10%. film, the dry texturing here is the RIE technology;

3) Diffusion of phosphorus source on the surface of silicon wafer after dry texturing, using POCl ₃ liquid phosphorus diffusion source to prepare PN junction, diffusion temperature of 830°C, time of 80min, sheet resistance of 60ohm, to obtain silicon wafer after phosphorus source diffusion;

4) wet-etching the silicon wafer after the phosphorus source is diffused, and then PECVD-depositing a SiNx anti-reflection film on its front surface with a thickness of 70nm, a reflectivity of 0.5%, and a SiNx film with a refractive index of 1.9 to obtain the deposited silicon piece;

5) Printing silver paste and aluminum paste on the back of the deposited silicon wafer, drying them, and then printing front silver on the front surface and sintering to obtain a finished battery. the

Example 3

Using the P-type polysilicon chip with a resistivity of 3 Ω cm as a diamond wire cut silicon chip, the method for making a battery of a diamond wire cut polysilicon chip comprises the following steps:

1) Pre-clean the P-type polysilicon wafer, remove the damaged layer with a thickness of 4 μm with a mixed solution of HNO ₃ and HF on the surface, and obtain the silicon wafer after removing the damaged layer;

2) Place the damaged silicon wafer in the reaction chamber of the texturing device, feed gas SF ₆ and O ₂ for dry texturing, the time is 10 minutes, the reflectivity after texturing is 15%, and the silicon wafer after dry texturing is obtained. film, the dry texturing here is the RIE technology;

3) Diffusion of phosphorus source on the surface of silicon wafer after dry texturing, using POCl ₃ liquid phosphorus diffusion source to prepare PN junction, diffusion temperature of 830°C, time of 80min, sheet resistance of 90ohm, to obtain silicon wafer after phosphorus source diffusion;

4) wet-etching the silicon wafer after the phosphorus source is diffused, and then PECVD-depositing a SiNx anti-reflection film on its front surface with a thickness of 90nm, a reflectivity of 3%, and a SiNx film with a refractive index of 2.3 to obtain the deposited silicon piece;

5) Printing silver paste and aluminum paste on the back of the deposited silicon wafer, drying them, and then printing front silver on the front surface and sintering to obtain a finished battery. the

Example 4

The performances of the batteries prepared in Examples 1-3 were compared with those prepared by the traditional method, as shown in Table 1:

Table 1 Comparison of battery conversion efficiency

It can be seen from Table 1 that the diamond wire-cut silicon wafer of the present invention is used to make cells using the present invention to obtain an ideal textured structure and to produce solar cells with low reflectivity, which improves the short-wave response and improves the conversion efficiency of solar cells. the

Claims (5)

1. the manufacture method of the battery of diamond wire cutting polysilicon chip, is characterized in that: comprise the steps:

1) P type polysilicon chip is carried out to prerinse, surface HNO ₃remove damage layer with HF mixed solution and obtain removing the silicon chip after damage layer;

2) silicon chip of removing after damage is placed on to fluff making device reative cell, passes into gas SF ₆with O ₂carry out dry method making herbs into wool, the time is 10min, obtains the silicon chip after dry method making herbs into wool;

3) silicon chip surface after dry method making herbs into wool carries out the diffusion of phosphorus source, adopts POCl ₃liquid phosphorus diffuse source is prepared P-N knot, 830 ℃ of diffusion temperatures, and the time is 80min, square resistance is 60 ~ 90ohm, obtains the silicon chip after the diffusion of phosphorus source;

4) silicon chip after the diffusion of phosphorus source is carried out to wet etching, then, at its front surface PECVD deposition SiNx film, obtain post-depositional silicon chip;

5) in post-depositional silicon chip back side difference printed silver slurry, aluminium paste post-drying, then sintering after the positive silver of its front surface printing, obtains battery finished product.

2. according to the manufacture method of the battery of claim 1 diamond wire cutting polysilicon chip, it is characterized in that: in step 1), the thickness of described removal damage layer is 2.5 ~ 4 μ m.

3. according to the manufacture method of the battery of claim 1 diamond wire cutting polysilicon chip, it is characterized in that: step 2) in, the reflectivity of the silicon chip after the making herbs into wool of RIE dry method is 5 ~ 15%.

4. according to the manufacture method of the battery of claim 1 diamond wire cutting polysilicon chip, it is characterized in that: in step 4), described SiNx antireflective coating THICKNESS CONTROL is at 70 ~ 90nm, and reflectivity is controlled at 0.5% ~ 3%, and refractive index is controlled at 1.9 ~ 2.3.

5. according to the manufacture method of the battery of the diamond wire cutting polysilicon chip described in any one in claim 1 ~ 4, it is characterized in that: the resistivity of described P type polysilicon chip is 1 ~ 3 Ω cm.