The plasma chemical vapor deposition of films of hydrogenated amorphous material was carried out while applying piezoelectric vibrations to the substrates, in the hope of enhancing surface migration of the precursors. A defect density which was of the order of 1015/cm3 was achieved in a film which was deposited at 120C under 2MHz vibrations. The photodegradation behavior of the films was measured by using pulsed ruby lasers and Xe lamps. It was found that prolonged light-soaking increased the defect densities in these films as well as in those which had been deposited without vibration. However, the saturated value for the former films remained at 3 x 1016/cm3, while that for the latter films was about 1017/cm3. The activation energy for the recovery from light-induced damage was higher for films which had been deposited under vibration than for films which had been deposited without vibration. It was concluded that piezoelectric vibration not only reduced the defect density in as-deposited films, but also improved the stability to light-soaking.

M.Sumiya, M.Kawasaki, J.Kocka, H.Koinuma: Japanese Journal of Applied Physics, 1995, 34[II-1B], L97-100