Structural properties of hot-wire a-Si:H deposited at rates in excess of 100 Angstrom /s

Mahan, A. H.; Perkins, J. D.; Nelson, B. P.; Gedvilas, L. M.; Xu, Y.; Vanecek, M.; Beyer, W.; Williamson, D. L.

doi:10.1063/1.1407317

Journal Article

Structural properties of hot-wire a-Si:H deposited at rates in excess of 100 Angstrom /s

Mahan, A. H. ; Xu, Y. ; Williamson, D. L. ; Beyer, W.FZJ* ; Perkins, J. D. ; Vanecek, M. ; Gedvilas, L. M. ; Nelson, B. P.

2001
American Institute of Physics Melville, NY

Journal of applied physics 90, 5038 - 5047 (2001) [10.1063/1.1407317]

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Please use a persistent id in citations: http://hdl.handle.net/2128/1928 doi:10.1063/1.1407317

Abstract: The structure of a-Si:H, deposited at rates in excess of 100 Angstrom /s by the hot wire chemical vapor deposition technique, has been examined by x-ray diffraction (XRD), Raman spectroscopy, H evolution, and small-angle x-ray scattering (SAXS). The films examined in this study were chosen to have roughly the same bonded H content C-H as probed by infrared spectroscopy. As the film deposition rate R-d is increased from 5 to > 140 Angstrom /s, we find that the short range order (from Raman), the medium range order (from XRD), and the peak position of the H evolution peak are invariant with respect to deposition rate, and exhibit structure consistent with a state-of-the-art, compact a-Si:H material deposited at low deposition rates. The only exception to this behavior is the SAXS signal, which increases by a factor of similar to 100 over that for our best, low H content films deposited at similar to5 Angstrom /s. We discuss the invariance of the short and medium range order in terms of growth models available in the literature, and relate changes in the film electronic structure (Urbach edge, as-grown defect density) to the increase in the SAXS signals. We also note the invariance of the saturated defect density versus R-d, measured after light soaking, and discuss possible reasons why the increase in the microvoid density apparently does not play a role in the Staebler-Wronski effect for this type of material. (C) 2001 American Institute of Physics.

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