DC Bias Effects on Growth of a-Ge:H in Coaxial-Type ECR Plasma

Abstract

Deposition conditions for obtaining high-quality a-Ge:H are investigated by means of a coaxial-type ECR plasma CVD reactor in which a substrate is placed along a magnetic field. The application of a negative bias to the substrate is found to be crucial to elimination of the postoxidation of deposited films, densification of the matrix, and improvement of the photoelectronic properties. This paper particularly focuses on the substrate bias effects on the structural and compositional inhomogeneities, film stress, chemical resistance and photoelectronic properties of a-Ge:H. The results are explained in terms of moderate ion bombardment caused by the substrate bias ranging from -50 V to -100 V.