HIGH-EFFICIENCY POLYCRYSTALLINE SILICON FILM SOLAR-CELLS

High-efficiency polycrystalline silicon film solar cells are fabricate d using gettering and low-temperature plasma-enhanced chemical vapor d eposition (PECVD) passivation schemes. Thin layers (similar to 10 nm) of PECVD SiO2 are used to passivate the emitter of the solar cell, whi le direct hydrogen rf plasma and PECVD silicon nitride (Si3N4) are imp lemented to provide emitter and bulk passivation of the cells. The com bination of Al and POCl3 gettering is found to be very effective in im proving the minority carrier diffusion length of the polycrystalline s ilicon film wafers and consequently, the efficiency of the solar cells . It is shown in this work that hydrogen rf plasma treatments can sign ificantly improve the solar cell's blue and long wavelength responses when performed through a thin layer of PECVD Si3N4. A very high effici ency for Si-supported film of 15.2% on 1 cm(2) area has been achieved using a simple solar cell process with Al/POCl3 gettering and low-temp erature passivation. (C) 1998 Published by Elsevier Science B.V. All r ights reserved.