High-open-voltage diffusion high-sheet-resistance process of PERC superposition SE

Abstract

The invention discloses a high-open-voltage diffusion high-sheet-resistance process of PERC superposition SE. The process comprises the following steps: S1, entering a boat; S2, vacuumizing and side leakage are conducted; S3, raising the temperature and carrying out low-concentration pre-oxidation; S4, carrying out constant-temperature high-concentration pre-oxidation; S5, carrying out low-temperature high-concentration oxygen deposition; S6, heating to deposit high-concentration oxygen; S7, raising the temperature and propelling; S8, propelling at constant temperature; and S9, cooling and discharging from the boat. Before the high-temperature propulsion is performed, the high concentration oxygen atmosphere is adopted, the thick oxide layer is used as a buffer medium layer, an actually deposited phosphorus source is controlled, the uniformity of phosphorus source deposition of the silicon wafer is facilitated, high-temperature propulsion is carried out in an oxygen-free atmosphere fora long time, the fact that a PN junction is high and deep is ensured, and two-step deposition is adopted for PN junction high junction depth and silicon wafer surface deposition; and, under the high-concentration oxygen flow atmosphere, the actual deposition source amount is controlled, the surface dead layer is reduced, the minority carrier lifetime is prolonged, long-time cooling is carried outunder the oxygen-free atmosphere, and then the low surface phosphorus concentration is guaranteed, and Uoc and Isc are guaranteed.

Description

technical field [0001] The invention relates to the technical field of monocrystalline silicon solar cells, in particular to a PERC superimposed SE high-opening-voltage diffusion high-square-resistance process. Background technique [0002] The cost reduction brought about by the iteration of crystalline silicon solar cell technology has gradually become the main driving force for the development of the industry. In the past two years, the photovoltaic industry cell technology has undergone a transformation from conventional BSF cells → PERC cells → PERC+LDSE cells, of which PERC+LDSE cells The process flow is: texturing→diffusion→laser SE→etching→back passivation→front PECVD→back PECVD→laser slotting→screen printing→sintering→testing. Only one laser SE process is added before the process, and the rest of the process remains unchanged. [0003] The laser SE process uses the phosphosilicate glass layer produced by the diffusion process as the dopant source, and uses the ther...

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Problems solved by technology

[0008] The invention mainly solves the problems of poor efficiency consistency between PERC+LDSE cells, unreasonable PN junction structure and low minority carrier lifetime in the existing technology; it provides a high opening pressure diffusion and high square resistance process of PERC superimposed SE, which is conducive to the preparation of high PERC+LDSE cell with square resistance, high junction depth, low surface phosphorus concentration and PN junction with high phosphorus concentration in PSG

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