The problem of hydrogenating this material without causing surface degradation was solved by exposing the surface to a H plasma via a thin SiNx(H) cap. This layer was permeable to H at the hydrogenation pressure of 250C, but was impermeable to P or PH3. It was found that shallow acceptors were heavily passivated, whereas shallow donors were only weakly affected. The presence of acceptors impeded H in-diffusion.

W.C.Dautremont-Smith, J.Lopata, S.J.Pearton, L.A.Koszi, M.Stavola, V.Swaminathan: Journal of Applied Physics, 1989, 66[5], 1993-6