Optical characteristics of hydrogenated amorphous silicon carbide films prepared at various gas flow rate ratios
Document Type
Article
Publication Date
1-1-2007
Abstract
Hydrogenated amorphous silicon carbide (a-SiC:H) films were prepared using a home-built plasma-enhanced chemical vapor deposition (PECVD) system with different flow rate ratios of methane (CH(4)) and silane (SiH(4)) gases. Fourier-transform infrared (FTIR) spectra indicate multiple bonding configurations consisting of wagging, bending and stretching modes of silicon, hydrogen and carbon atoms with a steady depletion of Si-H wagging and stretching modes as the gas flow rate ratio increases. Micro-Raman spectra show evidence of amorphous silicon structure in all the films. Only the a-SiC:H film prepared at the highest CH(4) to SiH(4) gas flow rate ratio shows the existence of the Si-C vibrational mode. All the samples prepared show room-temperature luminescence with two peaks centered at 467 and 698 nm. The photoluminescence (PL) intensity increases as the CH(4) to SiH(4) gas flow rate ratio increases but a reduction in intensity is observed for a high CH(4) to SiH(4) gas flow rate ratio. a-SiC:H films with higher optical energy gaps were obtained by allowing the gases to flow at higher CH(4) to SiH(4) gas flow rate ratios.
Keywords
hydrogenated amorphous silicon carbide photoluminescence PECVD chemical-vapor-deposition temperature deposition thin-films growth hwcvd
Divisions
PHYSICS
Publication Title
Japanese Journal of Applied Physics
Volume
46
Issue
10A
Publisher
IOP Publishing