Amorphous silicon films and solar cells deposited by HWCVD at ultra-high deposition rates

Abstract The deposition conditions for hydrogenated amorphous silicon, deposited by hot wire chemical vapor deposition, are linked to the film structure as we increase deposition rates (Rd) to >100 A/s. At low Rd ( 100 A/s), optimum films are deposited under silane depletion conditions as high as 75–80%, and all structural properties except for the SAXS results once again indicate a compact material. We relate changes in the film electronic structure (Urbach edge) with increasing Rd to the increase in the SAXS signals, and note the invariance of the saturated defect density versus Rd, discussing reasons why these microvoids do not play a role in the Staebler–Wronski effect for these films. Finally, we present device results over the whole range of Rd that we have studied and suggest why, at high Rd, device quality films can be deposited at such high silane depletions.