Surface and bulk effects in ex-situ hydrogenated α-SiC thin films

Abstract

Abstract The effect of ex-situ hydrogenation on the bulk and surface properties of amorphous SiC (α-SiC) thin films has been investigated using a number of bulk- and surface-sensitive characterisation techniques. The diffusion coefficient of deuterium in α-SiC is found to be equal to 3–4 × 10 −15 cm 2 s −1 . It is shown that atomic hydrogen causes drastic changes in the dielectric function, due to preferential Si etching from the film surface, and the formation of a carbon surface layer rich in sp 2 bonds. Furthermore, the atomic hydrogen diffuses in the bulk and causes an increase of the optical band gap and a concurrent decrease in conductivity, due to partial passivation of dangling bonds.