ISSN:
1077-3118
Source:
AIP Digital Archive
Topics:
Physics
Notes:
It is demonstrated that the stability of hydrogenated amorphous silicon (a-Si:H) is improved by deposition under the combined conditions of high substrate temperature (e.g., TD=400 °C) and high hydrogen dilution, as are readily achieved in a remote hydrogen plasma reactor. In comparison with optimized films from conventional rf glow discharge deposition (e.g., silane, 230 °C, 2 W), undoped high TD films possess a lower midgap defect density, the dark dc conductivity in n-type (phosphorus-doped) films displays higher equilibration temperatures and longer relaxation times at a given temperature with an activation energy of 1.0 eV, and undoped high TD films have a lower saturated density of light-induced defects. It is proposed that the ability to achieve the improved stability is a consequence of two effects: (1) the use of hydrogen dilution during deposition to maintain the hydrogen concentration in the film near 10 at. % even at 400 °C and (2) the possibility that at high TD's the hydrogen is more stably incorporated in the random network and/or that the density of weak Si—Si bonds is smaller.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.105282
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