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A front passivation process matching alkali throw selective emitter

A selective, emitter technology, applied in the direction of climate sustainability, sustainable manufacturing/processing, semiconductor devices, etc., can solve the serious problems of minority carrier recombination on the front surface of silicon wafers, reduce the surface recombination rate, and increase surface density Effect

Active Publication Date: 2020-12-22
SHANXI LUAN PHOTOVOLTAICS TECH
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  • Abstract
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  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The technical problem to be solved by the present invention is: how to solve the serious problem of minority carrier recombination on the front surface of the silicon wafer during the alkali polishing process

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0007] The specific realization of the pre-oxidation process is as follows:

[0008] 1. First, use a high temperature and low pressure oxidation furnace to deposit silicon dioxide. The deposition temperature is 790-810°C, the pressure is 100-120mbar, the deposition oxygen flow rate is 3000-3500sccm, and the time is 25-35min.

[0009] 2. Use a high-temperature and low-pressure oxidation furnace to deposit silicon dioxide and then cool down. The temperature drop is divided into three steps, firstly from 790-810°C to 740-760°C with a cooling rate of 3°C / min; then from 740-760°C to 700-720°C with a cooling rate of 5°C / min; 700-720°C drops to 650-670°C, the cooling rate is 7°C / min, and then the boat exits the tube.

[0010] The pre-silicon nitride film passivation process is realized as follows:

[0011] 1. Deposit the first silicon-rich film layer by PECVD. Deposition RF power 6500-7000W, deposition temperature 400-450°C, deposition pressure 1700mtorr, ammonia gas flow 1850-19...

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PUM

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Abstract

The invention relates to the field of single-crystal PERC back etching alkali polishing process and discloses a front passivation process matching an alkali polishing selective emitter. In an oxidation process before an alkali polishing process, the oxygen layer deposition with high-temperature hot oxygen and a slot cooling rate are combined, which means that a process condition for depositing anoxide layer comprises a deposition temperature of 790 to 810 DEG C, a pressure of 100 to 120 mbar, an oxygen flow 3000 to 3500 sccm and a time 25 to 35 min, the cooling process has three steps, and then a boat is taken out of a tube and an existing process is employed. In the alkali polishing process coating process, a layer of silicon-rich film is separately added, that is, a first layer of silicon-rich film is deposited by PECVD.

Description

technical field [0001] The invention relates to the field of single crystal PERC rear etching and alkali polishing technology. Background technique [0002] At present, the acid throwing process is mostly used in the backside etching of single crystal PERC, but the pressure of acid throwing on environmental protection and waste disposal has become a major obstacle to its future development. Alkali polishing process utilizes inorganic alkali reaction and does not contain fluorine and nitrogen. It has become a new direction for the development of single crystal PERC. However, alkali polishing laser selective emitter has become a major problem in the popularization and application of alkali polishing. Due to the control of the entire process of the alkali-polished laser selective emitter, the surface doping concentration is increased, and its hydrophilicity and difficult-to-etch characteristics are used to protect the laser on the front surface from over-etching. However, whil...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01L31/18H01L31/0216
CPCH01L31/02167H01L31/1804H01L31/1868Y02P70/50
Inventor 杨飞飞鲁贵林赵科巍张波张尧吕爱武杜泽霖李陈阳郭丽董建明邓铭
Owner SHANXI LUAN PHOTOVOLTAICS TECH
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