Hydrogenated microcrystalline silicon films were prepared by the rf magnetron-sputtering technique and structurally characterized by Raman spectroscopy, transmission electron microscopy, x-ray diffractometry, and infrared vibrational spectroscopy. The effects of variations of laser power and wavelength (and therefore energy) of incident radiation on the structure of hydrogenated microcrystalline silicon films were systematically studied by Raman scattering and transmission electron microscopy (TEM). With the increase in laser power, a phonon softening of the TO-like peak from 516 to 490 ${\mathrm{cm}}^{\mathrm{-}1}$ was observed, followed by a reversal of the trend with a further increment in laser power. TEM studies clearly revealed an increase in the amorphous phase for laser exposure in the power range where phonon softening was observed with subsequent enhancement in crystallinity for still higher powers.

• Received 13 August 1990

DOI:https://doi.org/10.1103/PhysRevB.43.4503