A depressurized diffusion process for preparing high square resistance cells

Abstract

The invention discloses a decompression diffusion technology for manufacturing high-square-resistance battery pieces. The technology comprises a constant-temperature decompression process, a pre-oxidation process, a temperature rise process, a deep diffusion process, a phosphorus propulsion process, a post-oxidation treatment process and a temperature drop and pressure rise process. Compared with a constant-pressure diffusion technology, the variable of pressure in the diffusion process is introduced into the decompression diffusion technology, the pressure in a diffusion furnace tube is reduced, meanwhile temperature, time and airflow are adjusted so that the uniformity of the diffusion square resistance can be better, and the photovoltaic conversion efficiency of the manufactured battery pieces can be higher; besides, the yield in unit time of equipment can be increased, and the usage amount of diffusion phosphorus sources is reduced.

Description

technical field [0001] The invention relates to the field of semiconductor electronic technology, especially the special technology for the production of crystalline silicon solar cells, and specifically relates to a diffusion technology for semiconductor wafers, especially crystalline silicon cells, to prepare emitters with doping. Background technique [0002] The main purpose of the diffusion process is to dope the semiconductor wafer under high temperature conditions, so as to change and control the type, concentration and distribution of impurities in the semiconductor, so as to establish regions with different electrical characteristics. In the manufacturing process of solar crystalline silicon cells, the thermal diffusion process is often used to prepare the PN junction, that is, under the condition of heating, the V group impurity element phosphorus is doped into the P-type silicon or the III group impurity boron is doped into the N-type silicon, and the PN junction i...

AI Technical Summary

Problems solved by technology

However, with the development of solar cells in the direction of high efficiency and low cost, the doping concentration on the surface of silicon wafers continues to decrease, the junction depth of PN junctions becomes shallower and shallower, and the sheet resistance continues to increase from 40 to 100Ω / port. The control of doping uniformity is getting worse and worse, making it difficult to fabricate high-quality shallow-surface PN junctions

In addition, due to the relatively small partial pressure of the dopant source, the absorption rate of the diffused phosphorus source in normal pressure diffusion is low, and the consumption is large, which has a great negative effect on tail gas treatment and environmental protection, and it is difficult to meet the high efficiency requirements of solar cells. , technical requirements for low-cost development

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