A-Si:H Deposited by Direct Photo-Cvd Using a Microwave-Excited Xe Lamp

A-Si:H films were deposited by direct decomposition of Si2H6 using vacuum ultra-violet light (147nm) emitted from a microwave-excited Xe resonance lamp. The substrate temperature was varied between 200 and 300 °C. The hydrogen content in the films is estimated to be comparable or lower than that in high-quality glow discharge (GD) films based on results from infrared absorption measurements and hydrogen effusion measurements. Hydrogen atoms are incorporated in the form of Si-H bonds (2000 cm−1 mode), and Si-Hn bonds of the 2090 mode In a unit volume was one or two order less than that of Si-H bonds (2000 cm−1 mode). In spite of the lower hydrogen content, the defect density was lower than that of GD films. The mobility gap of the photo-CVD film was closer to the optical gap. For both n- and p-type doping, the dark conductivity increased with the dopant gas composition monotonously, and reached the order of 10−3 S/cm.