a thin layer sio 2 Preparation method of passivation film and prepared battery

Abstract

The invention discloses a thin-layer SiO 2 The preparation method of the passivation film specifically includes the following steps: 1) firstly provide a PECVD equipment for chain continuous coating; 2) continuously transport the carrier plate loaded with silicon wafers into the process chamber of the chain PECVD equipment through a continuous conveying mechanism Realize coating; 3) In the process chamber, through the electrode plate air outlet of the plasma source, the 0 2 At the same time, SiH is released from the gas distribution block on the side of the electrode plate of the plasma source 4 , SiH 4 and O 2 The two gases enter different areas of the process chamber through different pipelines and flow out, meet and mix under a vacuum of 1-20Pa and form SiO on the surface of the continuously transported silicon wafer 2 passivation film. The invention only needs to use two kinds of special gas SiH 4 and O 2 As a reaction gas, and using a separate air intake method, it has the advantages of low process temperature, safety, reliability and environmental protection, and the dynamic chain continuous coating growth, high belt speed, large output, and highly controllable uniformity.

Description

technical field [0001] The invention relates to the technical field of high-efficiency solar cell preparation, in particular to SiO2 in batteries such as Topcon, POLO, IBC, and PERC. 2 The preparation method of passivation film and prepared Topcon, POLO, IBC, PERC and other batteries. Background technique [0002] In recent years, with the research and development of crystalline silicon solar cells, both theory and practice have proved that surface passivation is the only way to improve cell efficiency, and aluminum oxide thin layer passivation has been widely promoted on PERC cells. However, the passivation effect of doped polysilicon and silicon oxide stack is better, which is the prospect of the development of next-generation mass production technology. This is due to the chemical passivation effect of silicon oxide on the surface of crystalline silicon, and doped polysilicon has a good field passivation effect. But because silicon oxide is insulating, it prevents inter...

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Problems solved by technology

[0004] 1) Wet Nitric Acid Oxidation: Oxidize silicon wafers with high-temperature concentrated nitric acid for 4 minutes to form an extremely thin nano-SiO thin layer on the surface with a thickness of about 1.5nm. Environmental friendly;

[0005] 2) Thermal oxidation: Generally, tubular equipment is used, heated to a high temperature of about 570°C, and it takes about 30-60min to grow SiO with a thickness of about 2nm 2 Thin film has the disadvantages of high temperature, high energy consumption, long process time and high cost;

But since SiH 4 met O 2 will burn violently to form SiO 2 Dust particles, so that it is impossible to grow extremely thin SiO on silicon wafers 2 Thin film is also easy to contaminate the cavity, so the tubular equipment can only use N 2 O and SiH 4 As a reactive gas, the result is SiON instead of the desired SiO 2 , due to its grown SiO 2 The film contains higher N elements, and it is a SiON film instead of pure SiO 2 film, so the performance cannot meet the requirements

At the same time, N 2 O cost is also high

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