Hydrogen incorporation scheme in hydrogenated amorphous silicon/silicon carbon multilayers

Abstract

Using infrared absorption spectroscopy, we investigated the scheme of hydrogen incorporation into the well layer (a-Si:H) of a-Si:H/a-Si1−xCx :H (x=0.2, 0.5, and 0.8) multilayers fabricated by a glow discharge method. Hydrogen atoms are incorporated into the well layer in the form of the 2090-cm−1 mode, i.e., SiH monohydride bonds on internal microvoid surfaces or SiH2 dihydride bonds up to a well-layer thickness of 40 Å, and then SiH monohydride bonds of the 2000-cm−1 mode are formed. Even up to 100 Å, hydrogen atoms of the 2090-cm−1 mode are dominant rather than SiH monohydride bonds of the 2000-cm−1 mode. The optical energy gap of the multilayer is also discussed in connection with the scheme of hydrogen incorporation.