Front passivation process matching alkali polishing selective emitter

A selective and emitter technology, applied in the direction of climate sustainability, sustainable manufacturing/processing, electrical components, 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 , the effect of reducing the composite rate

Active Publication Date: 2019-11-05
SHANXI LUAN PHOTOVOLTAICS TECH
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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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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. The deposition RF power is 6500-7000W, the deposition temperature is 400-450°C, the deposition pressure is 1700mtorr, the...

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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 Applications(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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