Migration in doped and compensated hydrogenated amorphous material was measured using secondary ion mass spectrometry profiling at temperatures ranging from 155 to 300C (table 44). It was found that doping reduced the activation energy and enhanced the diffusion coefficient by up to 3 orders of magnitude at 200C. There was a correlation between the diffusion coefficient and the dangling-bond density. An analysis of 3 different diffusion models indicated that the breaking of weak Si-Si bonds by H could be an important process. The relationship between the diffusion results and the thermal equilibration of the electronic structure was considered.

R.A.Street, C.C.Tsai, J.Kakalios, W.B.Jackson: Philosophical Magazine B, 1987, 56[3], 305-20

Table 44

Diffusivity of H in Doped Amorphous Si