Structural Inhomogeneity in Hydrogenated Amorphous Silicon in Relation to Photoelectric Properties and Defect Density

Light-induced degradation of hydrogenated amorphous silicon (a-Si:H) is suppressed by applying a positive dc-bias to an rf-electrode (cathode) of a capacitively-coupled reactor at high deposition rate (2–2.7 nm/s) conditions. Reduction of the ion flux impinging on the growing film surface under positive dc-bias results in a decrease of the defect density, while the total content in the deposited films is almost independent of dc-bias. It is found that the defect density after light soaking is decreased by reducing the structural inhomogeneity, as confirmed by small-angle X-ray scattering analysis and electron spin resonance measurement.