The improved stability of hydrogenated amorphous silicon films grown by reactive magnetron sputtering at high substrate temperature

We report the electronic properties, stability, and microstructure of a-Si:H films grown at high substrate temperature (320-440°C) by dc reactive magnetron sputtering. The initial defect state density, determined by the constant photocurrent method, varies from 2-5×10¹⁵ cm ^-3 with H content changing from 15-10 at. % as T_s increases from 320-375°C. For 100 h of white light exposure at 1 W/cm ², the midgap state density reached an apparent saturation at 2-3×10¹⁶ cm^-3 over this temperature range. By contrast, films grown at 230-300°C saturate at 9×10¹⁶ cm^-3.