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Outer gettering method for silicon wafer

A silicon wafer and silicon wafer surface technology, applied in the field of integrated circuits and solar energy applications, can solve problems such as reducing the photoelectric conversion efficiency of solar cells, and achieve the effects of improving the quality of silicon wafers, good gettering effect, and low cost

Active Publication Date: 2012-05-30
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The solar cell is a bulk device, and the defect region generated by internal gettering happens to be in the body, which will become a recombination center for minority carriers, greatly reducing the photoelectric conversion efficiency of the solar cell

Method used

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  • Outer gettering method for silicon wafer
  • Outer gettering method for silicon wafer
  • Outer gettering method for silicon wafer

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] (1) Take a single crystal silicon wafer, the thickness is about 200 microns, and the minority carrier lifetime is about 13 μs after testing;

[0025] (2) Indium source (0.01mol / L InCl 3 solution) double-sided coating on the surface of single crystal silicon;

[0026] (3) Pass oxygen into the RTP-300 rapid heat treatment furnace, the gas flow rate is about 1L / min, and send the monocrystalline silicon wafer treated in step (2) into the furnace, and the furnace temperature is raised to 900°C at 50°C / s , after 3 minutes of heat preservation, cool down to room temperature with the furnace;

[0027] (4) Soak in hydrofluoric acid (10% by volume) for 30s to remove the surface glass layer.

Embodiment 2

[0034] (1) Take a monocrystalline silicon wafer contaminated by iron impurities, the thickness is about 600 microns, and the minority carrier lifetime is about 0.3 μs after testing;

[0035] (2) Indium source (0.05mol / L of In 2 (SO 4 ) 3 solution) double-sided coating on the surface of single crystal silicon;

[0036] (3) Pass oxygen into a conventional heat treatment furnace, the gas flow rate is about 1L / min, and the temperature in the furnace rises to

[0037] 900°C, put the above-mentioned monocrystalline silicon wafer into the furnace, keep it warm for 120 minutes, and then cool down to room temperature with the furnace;

[0038] (4) Soak in hydrofluoric acid (10% by volume) for 30s to remove the surface glass layer.

[0039] figure 2 A comparison chart of minority carrier lifetimes of single crystal silicon wafers contaminated with iron impurities before and after treatment in Example 2 is given. Depend on figure 2 It can be seen that the minority carrier lifeti...

Embodiment 3

[0041] (1) Take a copper-contaminated single-crystal silicon wafer, the thickness is about 200 microns, and the minority carrier lifetime is about 2 μs after testing;

[0042] (2) Indium source (0.02mol / L In(NO 3 ) 3 solution) double-sided coating on the surface of single crystal silicon;

[0043] (3) Pass oxygen into the RTP-300 rapid heat treatment furnace, the gas flow rate is about 1L / min, and send the monocrystalline silicon wafer treated in step (2) into the furnace, and the furnace temperature is raised to 800°C at 50°C / s , after 6 minutes of heat preservation, cool down to room temperature with the furnace;

[0044] (4) Soak in hydrofluoric acid (10% by volume) for 30s to remove the surface glass layer.

[0045] image 3 A comparison chart of minority carrier lifetimes of single crystal silicon wafers contaminated with copper impurities before and after treatment in Example 3 is given. Depend on image 3 It can be seen that the minority carrier lifetime of the mo...

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Abstract

The invention discloses an outer gettering method for a silicon wafer, which comprises the following steps of: coating an indium source on a surface of the silicon wafer; and putting the silicon wafer into a conventional heat treatment boiler or a fast heat treatment boiler for heat preservation for a while under the atmosphere of oxygen, cooling the silicon wafer to make the temperature of the silicon wafer equal to room temperature, and soaking the silicon wafer into a hydrofluoric acid to remove a surface glass layer, wherein a heat-preservation temperature is 700-1,000 DEG C, time for heat preservation in the conventional heat treatment boiler is 30-120 minutes, and the time for heat preservation in the fast heat treatment boiler is 1-10 minutes. The method is simple in operation, lowin cost and quite good in gettering effect.

Description

technical field [0001] The invention belongs to the field of integrated circuits and solar energy applications, and in particular relates to a silicon chip external gettering method. Background technique [0002] Gettering technology refers to intentionally creating various crystal defects inside or on the back of the silicon wafer to attract metal impurities to precipitate at these defects. It is an effective method to reduce the impurity content in the silicon wafer. According to the position of the gettering point, it can be divided into external gettering and internal gettering. [0003] Internal gettering refers to a high-temperature-low-temperature-high temperature multi-step heat treatment process, using the properties of oxygen diffusion and precipitation during heat treatment, to generate a large amount of oxygen precipitation inside crystalline silicon, and using oxygen precipitation as a gettering center to bind metal impurities in it. The surrounding surface for...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01L21/02H01L21/322
Inventor 余学功肖承全杨德仁
Owner ZHEJIANG UNIV
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