Electrode distance between cathode and anode is one of the important parameters for fabricating hydrogenated amorphous silicon (a-Si:H) using plasma-enhanced chemical-vapor-deposition system with parallel plate electrodes. In this work, we have investigated the relationship between electrode distance and stability of a resulting a-Si:H. The stability is improved with decreasing electrode distance. At shorter electrode distance, formation of higher silane-related-reactive species is suppressed by heating effect of gas molecules near the cathode due to a proximity to the heated anode. Using cathode heating method, the stability of a-Si:H is improved even at long electrode distances. (C) 2002 Elsevier Science B.V. All rights reserved.