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Nano-silicon-boron paste and its application to the process of preparing fully shielded boron back field

A technology of nano-silicon-boron paste and boron back field, applied in the field of nano-materials, to reduce production costs, solve warping of silicon wafers, and improve yield

Active Publication Date: 2016-08-17
苏州金瑞晨科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is to provide a nano-silicon-boron paste and its application to the process of preparing a fully shielded boron back field, because the solid solubility of boron in silicon is higher than that of aluminum, it is easy to make a "full shield" boron back field, so that Boron back field instead of aluminum back field will completely solve the warping problem of silicon wafers, improve the yield, and solve the warping problem of silicon wafers, which will help reduce the thickness of silicon wafers and save costs

Method used

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  • Nano-silicon-boron paste and its application to the process of preparing fully shielded boron back field
  • Nano-silicon-boron paste and its application to the process of preparing fully shielded boron back field
  • Nano-silicon-boron paste and its application to the process of preparing fully shielded boron back field

Examples

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Embodiment 1

[0041] A kind of nano-silicon-boron slurry, viscosity is 9PaS, described nano-silicon-boron slurry contains 65 parts of sandalwood, 15 parts of terpineol, 4 parts of boron, 1 part of ethyl cellulose, 15 parts of silicon powder, and described silicon powder particle The diameter is 50nm ~ 150nm.

[0042] The process of using the above nano-silicon-boron paste to prepare a fully shielded boron back field is carried out in the following steps: 1. Silicon wafer cleaning and flocking; 2. Printing and drying nano-silicon-boron paste; 3. Boron diffusion; 4. POCl 3 Diffusion; 5. Cleaning of phosphosilicate glass; 6. Deposition of passivation / anti-reflection film; 7. Printing and drying of metal electrodes; 8. Sintering of metal electrodes; step 2, printing boron paste to fully cover the back of the silicon wafer; drying of boron paste Carry out in an air atmosphere on a heating plate, the drying temperature is 350° C., and the drying time is 5 minutes. After drying, the silicon parti...

Embodiment 2

[0044] A nano-silicon-boron slurry with a viscosity of 6 PaS. The nano-silicon-boron slurry contains 75 parts of sandalwood, 5 parts of boron, and 20 parts of silicon powder. The particle size of the silicon powder is 50-150 nm.

[0045] The process of preparing the boron back field using the above-mentioned nano-silicon-boron slurry includes the following steps: 1. Cleaning the p-type silicon wafer and flocking; 2. Printing and drying the nano-silicon-boron slurry; 3. POCl 3 Diffusion; 4. Cleaning of phosphosilicate glass; 5. Deposition of passivation / anti-reflection film; 6. Printing and drying of metal electrodes; 7. Sintering of metal electrodes. The boron paste printing described in step 2 fully covers the back of the silicon wafer. Drying is carried out on a heating plate, the drying temperature is 200° C., and the drying time is 5 minutes. After drying, the silicon particles in the boron slurry remain granular and accumulate naturally, and their appearance is as follow...

Embodiment 3

[0047] A nano-silicon-boron slurry with a viscosity of 6PaS. The nano-silicon-boron slurry contains 75 parts of sandalwood, 5 parts of boron, and 20 parts of silicon powder. The particle size of the silicon powder is 50nm-150nm.

[0048] The process of preparing the boron back field by using the above-mentioned nano-silicon-boron slurry includes the following steps: 1. Cleaning the p-type silicon wafer and flocking; 2. Printing and drying the nano-silicon-boron slurry; 3. Boron diffusion; 4. POCl 3 Diffusion; 5. Cleaning of phosphosilicate glass; 6. Deposition of passivation / anti-reflection film; 7. Printing and drying of metal electrodes; 8. Sintering of metal electrodes. The boron paste printing in step 2 is selected to fully cover the back of the silicon wafer. Drying is carried out on a heating plate, the drying temperature is 200° C., and the drying time is 5 minutes. After drying, the silicon particles in the boron slurry remain granular and naturally piled up, and thei...

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Abstract

The invention discloses nanometer borosilicate slurry and a process for applying the nanometer borosilicate slurry to preparation of a full-shielding boron back surface field. On the basis of a production process of common batteries, the nanometer borosilicate slurry is added in a printed mode to form the boron back surface field which has a full-shielding effect to replace an existing aluminum back surface field, so that the problem of silicon wafer warpage caused by the aluminum back surface field is solved, fragments are reduced, and yield is improved. In addition, as the electric field intensity of the boron back surface field is higher than that of the aluminum back surface field, photon-generated carriers can be more effectively prevented from overflowing out of the surface or the interface of a silicon wafer for recombination. Meanwhile, silicon granules in the nanometer borosilicate slurry are crosslinked and form a layer of compact structure which is tightly connected to a substrate of the silicon wafer in an adhesive mode, so that diffusion and mutual interference of boron and phosphorus can be effectively prevented.

Description

technical field [0001] The invention belongs to the field of nanometer materials, and in particular relates to a nanometer silicon boron paste and a process for preparing a fully shielded boron back field. Background technique [0002] Currently, crystalline silicon solar cells usually use aluminum back field technology. The aluminum back field is usually formed when the aluminum electrode on the back of the battery is sintered. The eutectic point of the silicon-aluminum system is 537°C. Through mutual melting, aluminum dissolves into crystalline silicon. Thereby doping the silicon to form an aluminum back field. Aluminum backfields have two distinct disadvantages. First, due to the limitation of the solid solubility of aluminum in silicon, the concentration and depth of aluminum on the surface of the silicon wafer cannot meet the requirements of "full shielding" of the back field, resulting in a decrease in cell efficiency. Second, when aluminum electrodes are sintered...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01B1/18H01L31/0224H01L31/18
CPCY02P70/50
Inventor 刘国钧将红彬万剑沈晓燕程亮沈晓东
Owner 苏州金瑞晨科技有限公司