A diffusion process for improving square resistance uniformity

Abstract

The invention discloses a diffusion process for improving square resistance uniformity, comprising the following steps of: (1) heating up: inserting a silica wafer after velvet making into a quartz boat, boating, and heating the furnace tube to 750 DEG C to 795 DEG C after entering the boat; (2) Dry oxygen oxidation: Dry oxygen was introduced to oxidize, the flow rate of dry oxygen was 1800-2200ml / min, and the oxidation time was 100ecs; (3) wet oxygen oxidation: wet oxygen was introduced for oxidation, the flow rate of wet oxygen was 1400-1600 ml / min, the oxidation time was 200sec; (4) Diffusion: Dry oxygen intake, small nitrogen and large nitrogen are precipitated and diffused, 600-900 ml / min of dry oxygen flow rate, 1200-1500ml / min of small nitrogen flow rate, 10000ml / min to 15000ml / minof large nitrogen flow and diffusion at 750 DEG C to 795 DEG C for 1200 sec. The invention provides a diffusion process which improves the uniformity of square resistance with good quality, high uniformity and good uniformity of square resistance between the edge and the periphery of the diffused silicon wafer.

Description

technical field [0001] The invention relates to the technical field of crystalline silicon cell solar cell production, and in particular relates to a diffusion process for improving square resistance uniformity. Background technique [0002] In terms of the industrialization of crystalline silicon cells, high-temperature diffusion methods are usually used to prepare PN junctions, and the industrial preparation of high-resistance emitters with good inter-chip and intra-chip uniformity is an important way to improve battery conversion efficiency and electrical performance stability. It can improve the optimization space of the diffusion process as a whole, and can reduce the number of battery efficiency bins. According to the existing technology, in order to increase the production capacity, the spacing between silicon wafers is continuously reduced. The adjacent distance between silicon wafers is small, and the partial pressure ratio of doped atoms is small, resulting in a la...

AI Technical Summary

Problems solved by technology

The adjacent distance between silicon wafers is small, and the partial pressure ratio of doped atoms is small, resulting in a large gap between the doping concentration in the middle of the silicon wafer and the edge, poor diffusion process quality, low uniformity, and in production lines with high square resistance, Due to the higher square resistance, the non-uniform phenomenon increases, resulting in more uneven square resistance between the edge of the diffused silicon wafer and the surrounding area.

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