Authors: Fatemeh Shariatmadar Tehrani Saadah Abdul Rahman
Publish Date: 2014/03/27
Volume: 25, Issue: 5, Pages: 2366-2373
Abstract
Silicon carbide SiC thin films were deposited using hot wire chemical vapor deposition HWCVD technique from pure silane and methane gas mixture The effect of filament distance to the substrate on the structural and optical properties of the films was investigated Fourier transform infrared FTIR spectroscopy Xray diffraction XRD Raman scattering spectroscopy and UV–Vis–NIR spectroscopy were carried out to characterize SiC films XRD patterns of the films indicated that the film deposited under highest filamenttosubstrate distance were amorphous in structure while the decrease in distance led to formation and subsequent enhancement of crystallinity The Si–C bond density in the film structure obtained from FTIR data showed significant increment with transition from amorphous to nanocrystalline structure However it remained almost unchanged with further improvement in crystalline volume fraction From Raman data it was observed that the presence of amorphous silicon phase and sp 2 bonded carbon clusters increased with the decrease in distance This reflected in deterioration of structural order and narrowing the optical band gap of SiC films It was found that filamenttosubstrate distance is a key parameter in HWCVD system which influences on the reactions kinetics as well as structural and optical properties of the deposited films
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