Proton-magnetic-resonance studies of microstructure in plasma-deposited amorphous-siliconhydrogen films

Abstract

Proton-magnetic-resonance data are presented for twenty different plasma-deposited amorphous-siliconhydrogen films. The two-phase compositional inhomogeneity observed in these films is found to be independent of film thickness down to less than 1 m. Models for various structural configurations show that these films contain heavily monohydride-clustered regions such as vacancies and voids, as well as (SiH2)n and SiH3 local bonding configurations. The films also contain regions in which monohydride groups are distributed at random. Based on changes in a film whose proton NMR line shapes are metastable as deposited, a model based on strain relief is proposed for film development which explains the ubiquitous presence of the two-phase inhomogeneity. Examination of the changes in proton NMR data as a function of deposition conditions furnishes new insight on the role SiH2 and SiHx+ groups have in models for the gas-phase reactions involved in the developing films. Finally, p- or n-type doping is found to increase the hydrogen content of the films, and, under heavy p-type doping with diborane, boron clustering may occur within the films. © 1981 The American Physical Society.