Dc. Marra et al., SILICON HYDRIDE COMPOSITION OF PLASMA-DEPOSITED HYDROGENATED AMORPHOUS AND NANOCRYSTALLINE SILICON FILMS AND SURFACES, Journal of vacuum science & technology. A. Vacuum, surfaces, and films, 16(6), 1998, pp. 3199-3210
Citations number
63
Categorie Soggetti
Physics, Applied","Materials Science, Coatings & Films
In situ attenuated total reflection Fourier transform infrared spectro
scopy was used to study the H bonding on the surfaces of a-Si:H and nc
-Si:H during plasma enhanced chemical vapor deposition from SiH4/H-2/A
r containing discharges. Well-resolved SiHx (1 less than or equal to x
less than or equal to 3) absorption lines that correspond to the vibr
ational frequencies commonly associated with surface silicon hydrides
were detected. During deposition of a-Si:H films using SiH4 without H-
2 dilution; the surface coverage was primarily di- and trihydrides, an
d there are very few dangling bonds on the surface. In contrast, durin
g deposition of nc-Si:H using SM, diluted with H-2, the amount of di-
and trihydrides on the surface is drastically reduced and monohydrides
dominate the surface. Furthermore, the vibrational frequencies of the
monohydrides on nc-Si:H film surfaces match well with the resonant fr
equencies of monohydrides on H terminated Si (111) and Si (100) surfac
es. The decrease of higher hydrides on the surface upon H-2 dilution i
s attributed to increased dissociation rate of tri- and dihydrides on
the surface through reaction with dangling bonds created by increased
rate of H abstraction from the surface. Results presented are consiste
nt with SiH3 being at least one of the precursors of a-Si:H deposition
. (C) 1998 America Vacuum Society. [S0734-2101(98)05506-7].