STRUCTURAL STUDIES ON HYDROGENATED AMORPHOUS GERMANIUM-CARBON FILMS PREPARED BY RF-SPUTTERING

ESR signals for hydrogenated amorphous Ge-C alloy films prepared by ma gnetron sputtering were deconvoluted into signals originating from a G e dangling bond and a C dangling bond. It was determined from the resu lts of the deconvolution that the number of Ge dangling bonds per Ge a tom is ten to sixty times larger than that of C dangling bonds per C a tom. 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 conte nt 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 i n Ge-C alloy films, although the density of C-H bonds increases. This finding may he caused by an increase in the structural randomness beca use the difference in the covalent bond radius between Ge and C is qui te large.