Microwave-Excited Plasma CVD of a-Si:H Films Utilizing a Hydrogen Plasma Stream or by Direct Excitation of Silane

Abstract

The microwave-excited plasma CVD of a-Si:H films, in which SiH 4 was decomposed by a plasma stream of hydrogen or by direct excitation at low gas pressures (10 -4 to 10 -3 Torr), was examined and compared with a previously studied Ar plasma stream method. It was clarified that an Ar plasma stream was not necessary to obtain highly photoconductive a-Si:H films. However, the deposition characteristics in these deposition methods were different from the Ar plasma stream method. On the other hand, the influence of the hydrogen plasma stream was not apparent when the SiH 4 flow rate was high, suggesting an ionization cross-section dependence of the plasma discharge.