Effect of in situ boron doping on properties of silicon germanium films deposited by chemical vapor deposition at 400 degrees C

This paper reports on the role of boron in situ doping on enhancing crystal lization of silicon germanium deposited at 400 degreesC and 2 torr. The dep endence of growth rate on germanium content and boron concentration is inve stigated. The minimum boron concentration and the minimum germanium content required for crystallizing the as-grown layers is experimentally determine d. The texture and grain microstructure of doped and undoped poly SiGe laye rs has been investigated by means of x-ray diffraction spectroscopy and tra nsmission electron microscopy. The low deposition temperature coupled with the low tensile stress of the polycrystalline material enable postprocessin g of surface micromachined microelectromechanical systems on top of standar d complementry metal oxide semiconductor wafers with Al interconnects. Furt hermore, the resistivity of the as-grown layers is as low as 1 m Omega cm, and hence, it can be used as a seeding layer for polycrystalline Si solar c ells compatible with glass substrates.