The sites, gap levels, and migration barriers of interstitial H in Si were predicted. The hydrogenation of C-rich Si results in the formation of H2*(C) and C2H2, in contrast to FZ-Si where H2 molecules dominate. The fully saturated vacancy (VH4) also forms. This complex was normally stable up to 650C. However, in C-rich Si, VH4 anneals around 550C while the VH3HC complex appeared. There, C replaced one of the four Si nearest-neighbours to the vacancy. This implied that VH4 began to diffuse at 550C, and then trapped at Cs. This in turn implied that all the VHn complexes (n = 1, 2, 3, 4) were mobile at moderate temperatures. Here, the energetics of H in Si were considered and the key experimental and theoretical results concerning H interactions in C-rich Si were summarized with regard to the migration paths and activation energies of the four VHn complexes.

Hydrogen in C-Rich Si and the Diffusion of Vacancy-H Complexes. S.K.Estreicher, A.Docaj, M.B.Bebek, D.J.Backlund, M.Stavola: Physica Status Solidi A, 2012, 209[10], 1872-9