Laser Doping and Recrystallization for Amorphous Silicon Films by Plasma-Enhanced Chemical Vapor Deposition

摘要

One of the most challenging problems to develop polycrystalline silicon thin-film solar cells is the growth of crystalline silicon on foreign, low-cost and low-temperature substrates. In this paper, a laser doping technique was developed for the plasma-deposited amorphous silicon film. A process combination of recrystallization and dopant diffusion (phosphorous or boron) was achieved simultaneously by the laser annealing process. The doping precursor was synthesized by a sol-gel method and was spin-coated on the sample. After laser irradiation, the grain size of the doped polycrystalline silicon was examined to be about 0.5-1.0 urn. The concentrations of 2×10~(19) and 5× 10~(18) cm~(-3) with Hall mobilities of 92.6 and 37.5 cm~2/V-s were achieved for the laser-diffused phosphorous- and boron-type polysilicon films, respectively.