Infrared spectroscopy and transmission electron microscopy of polycrystalline silicon carbide

The polycrystalline structure of silicon carbide was investigated by infrar ed spectroscopy and transmission electron microscopy (TEM). The films were obtained by annealing in the temperature range 950-1250 degreesC of amorpho us silicon carbide films deposited on a silicon substrate by PECVD, The bro ad absorption band at around 750 cm(-1) in the infrared spectrum of amorpho us material after annealing at high temperature changes from a Gaussian to a Lorentzian shape, corresponding to the transition from an amorphous to a polycrystalline phase. The SiC peak becomes sharper with increasing the ann ealing temperature, this effect being related to the growth of crystalline grains. TEM microscopy indicates that the crystallisation occurs homogeneou sly in the films and the diffraction pattern shows that the film crystallis es into cubic 3C-SiC. The distribution of polycrystalline grains as determi ned by TEM evidences an increase of the grain size with increasing the anne aling temperature. A correlation between infrared peak width and mean grain radius has been found. (C) 2001 Elsevier Science Ltd, All rights reserved.