Electron spin resonance was studied in situ during the exposure of hydrogenated amorphous films to atomic H that was generated by a remote plasma. A diffusion coefficient which was greater than 10-10cm2/s was observed for free atomic H in the films in the initial stage of H treatment. The H created additional dangling bonds (about 1013/cm3) during in-diffusion. The diffusion of such free H was a self-limiting process. The dangling bonds which were created in the initial stage of H exposure acted as trapping sites for impinging H atoms. As a result, the effective diffusion coefficient decreased with H treatment time. The reported effective diffusion coefficient for plasma in-diffusion of H with a relatively wide time-span was considered to be the resultant of the diffusion of free H and bonded H. The characteristic depth of the dangling-bond distribution decreased with increasing H treatment temperature. The activated rate constants of dangling-bond creation reactions dominated activated free-H diffusion in determining the distribution of additional dangling bonds at various treatment temperatures.

In situ ESR Study to Detect the Diffusion of Free H and Creation of Dangling Bonds in Hydrogenated Amorphous Silicon. U.K.Das, T.Yasuda, S.Yamasaki: Physical Review B, 2001, 63[24], 245204 (9pp)