Defects in hydrogenated amorphous silicon-carbon alloy films prepared by glow discharge decomposition and sputtering

Abstract

Properties of hydrogenated amorphous silicon-carbon alloy (a-Si1−xCx :H) films prepared by radio frequency (rf) glow discharge decomposition and rf sputtering have been investigated by means of electron spin resonance (ESR), infrared absorption, optical absorption, and photoconductivity measurements. Although the number of C-H per C atom [C-H]/[C] is larger than that of Si-H per Si atom [Si-H]/[Si], the ESR spin density increases greatly with the C content. The increase in the density of dangling bonds may be related to the fact that the number of H atoms in gathered phase increases with an increase in x. ESR measurements also give useful information about the preferential formation of C or Si dangling bonds and the atomic distribution of Si and C through a compositional dependence of the g value. A remarkable feature for a-Si1−xCx :H film is that the presence of C atoms in the amorphous network makes the Si-H bond in a-Si1−xCx :H more stable than that in a-Si:H.