Structural studies on hydrogenated amorphous germanium-carbon films prepared by RF sputtering

ESR signals for hydrogenated amorphous Ge-C alloy films prepared by magnetron sputtering were deconvoluted into signals originating from a Ge dangling bond and a C dangling bond. It was determined from the results of the deconvolution that the number of Ge dangling bonds per Ge atom is ten to sixty times larger than that of C dangling bonds per C atom. In contrast to the case of Ge-Si alloy films, in which the number of Ge dangling bonds per Ge atom decreases by increasing the Si content because of the increase in the density of Si-H bonds, the number of Ge dangling bonds per Ge atom increases by increasing the C content in Ge-C alloy films, although the density of C-H bonds increases. This finding may he caused by an increase in the structural randomness because the difference in the covalent bond radius between Ge and C is quite large.