Hydrogenated amorphous silicon films deposited at high growth rates by the cathode heating technique: properties and light induced degradation

The deposition of hydrogenated amorphous silicon (a-Si:H) films at high growth rates (≈ 10 Å/s) by plasma enhanced chemical vapour deposition, showing acceptable optoelectronic properties, was achieved by impeding powder growth in the plasma through heating of the cathode and hydrogen dilution of the source gas silane. In view of the high rf power densities used for film growth, the properties of the films in the surface and near surface regions were studied together with that of the bulk. Light induced degradation of the samples deposited under conditions where powder growth in the plasma was suppressed as well as conditions of dusty plasma were studied. Changes in the generation efficiency × mobility × lifetime product and the defect density were monitored with light soaking time.