EVALUATION OF CONTRIBUTION OF HIGHER-ORDER SILANE RADICALS IN SILANE DISCHARGES TO Si-H_2 BOND FORMATION IN A-SI:H FILMS

摘要

We have discussed whether higher-order silane (HOS) radicals are the origin of Si-H_2 bonds in a-Si:H films, or not, based on the results of discharge power dependence of SiH_4, Si_2H_6, and Si_2H_8 densities, which has been understood using the simple reaction model. While the ratios of [Si_mH_(2m+2)]/[SiH_4] (m= 2 and 3), which are regarded as the contribution ratio of HOS radicals to the film growth, have constant values, the density of Si-H_2 bonds in the films C_(SiH2) varies by more than one and a half orders of magnitude. The lack of correlation between the ratios and the C_(SiH2) value strongly suggests that the HOS radicals do not mainly contribute to formation of Si-H_2 bonds in a-Si:H films.