Comparative study of hydrogen stability in hydrogenated amorphous and crystalline silicon

The dependence of hydrogen effusion and diffusion on hydrogen concentration was studied for crystalline and amorphous Si:H samples which were hydrogen ated by hydrogen ion implantation. The results are compared to data for a-S i:H and mu c-Si:H films grown with various H concentrations. Although gener al trends of the H concentration dependence of H stability are similar, the re are differences between cSi:H and a-Si:H. These differences involve larg er hydrogen-generated microstructural effects in c-Si:H and a hydrogen diff usion coefficient in compact material increasing in a-Si:H and decreasing i n c-Si:H with increasing H concentration. A different flexibility of the at omic network in amorphous and crystalline Si could be the origin, Microcrys talline Si:H films show a similar concentration dependence of H diffusion a s a-Si:H. (C) 2000 Elsevier Science B.V. All rights reserved.