Stable a-Si:H fabricated from halogenous silane by ECR hydrogen plasma

Abstract

A-Si:H stable against light soaking was fabricated from SiCl 2H 2 fed into an activated hydrogen flow generated by an ECR plasma. Both hydrogen content (CH, at.%) and optical gap (Eg, eV) were reduced simultaneously with increasing substrate temperature (Ts, °C), which implies that structural relaxation is enhanced at the growing surface due to a strong interaction of hydrogen and chlorine. Meanwhile, hydrogen in the Si network was reduced to 6 at.% at a Ts of 220 °C or lower by hydrogen treatment without reducing the optical gap. These films showed some attractive features, viz., low electric conductivity of < 10 −13 (S/cm) at room temperature and low defect density, (3–5)× 10 15 (cm −3) in the annealed state and (3–5)× 10 16 (cm −3) in the saturated state after prolonged light illumination.