Optical, electrical and structural properties of amorphous SiCN:H ®lms prepared by rf glow-discharge decomposition

Amorphous quaternary alloy (a-SiCN:H) ®lms composed of silicon, carbon, nitrogen and hydrogen have been prepared by the rf glow-discharge decomposition in a gas mixture of methane, silane, nitrogen and helium. Effects of nitrogen addition on the optical, electrical, structural and optoelectronic properties of the ®lms have been investigated. Optical bandgap remains almost constant for a wide range of nitrogen addition. Dark and photoconductivity becomes greater by the nitrogen addition than those of undoped a-SiC:H ®lms. Incorporation of a small amount of nitrogen in the ®lm is likely to reduce the structural disorder and/or the density of defects, and some nitrogen atoms seem to work as a dopant. On the other hand, large incorporation deteriorates these properties. The nitrogen addition effect appears more remarkably in the ®lms prepared under the low ¯ow rate ratio of methane to silane. # 2001 Published by Elsevier Science B.V.