Photoinduced effects in RF and VHF a-Si:H films deposited with different ion bombardment

Hydrogenated amorphous silicon (a-Si:H) films were deposited in a diode-type reactor in RF and VHF discharge under controlled ion bombardment. Defect concentration in the films was studied as a function of the energy of ions impinging on the growing film in as-grown (A), light-soaked (B), and annealed states (C). Significant changes in defect concentration, and Fermi-level position with ion energy were observed in the samples in A-and C-states, while ion bombardment caused less changes in the properties in the B-state. The data obtained are discussed in terms of the generation of D₀ and D_- defect states, which are controlled by ion bombardment of the films during growth.