Additional post-glass-removal processes for enhanced cell efficiency in the production of solar cells

Abstract

A method is provided for the production of solar cells from raw crystalline p-type silicon wafer material. The surface condition prior to SiNx deposition is improved by providing additional process steps following the phosphorous glass removal and prior to the SiNx anti-reflection coating deposition. In one embodiment, the wafer is submitted to a thermal anneal under oxygen atmosphere followed by a wet-chemical oxide removal. The anneal reduces the surface phosphorous concentration by diffusion, reduces lattice defects in the emitter and oxidizes the silicon surface. In another embodiment, both a surface oxide is obtained and subsequently removed with wet chemistry. This sequence allows for an integration of the phosphorous glass removal, the wet-chemical oxidation, and the SiOx removal into a single machine.