Microstructure evolution of hydrogenated silicon thin films at different hydrogen incorporation

This paper describes the microstructure evolution of hydrogenated silicon films containing various amounts of hydrogen. Microcrystalline silicon films were produced when the hydrogen content of the films was adjusted by using the diluted-hydrogen methods. Polycrystalline silicon films having grain sizes in the micrometer range were deposited at low temperature (250°C) by ECR-CVD with the hydrogen-dilution method. The microcrystalline and polycrystalline films were characterized by NMR, FTIR, Raman, X-ray and optical spectroscopy and electrical measurements. The results evaluate the possibility of even larger grain silicon films suitable for high performance solar cells which avoid the fundamental difficulties of amorphous Si:H solar cells.