Interelectrode separation effects on a-SiGe:H films prepared by plasma chemical vapor deposition

The properties of a-SiGe:H films prepared by the glow discharge plasma CVD method at various interelectrode separation were studied systematically. This study was done at two different rf power densities. It has been found that interelectrode separation plays an important role in determining film properties. It shows a more marked effect on photosensitivity at lower rf power density than at higher rf power density. Photosensitivity, in general, decreased, whereas growth rate increased with the increase in interelectrode separation. High photosensitivity (1.3×10 5) was obtained even at higher growth rate (245 Å/min) just by controlling the interelectrode separation. Bandgap of the films was about 1.4 eV. Structural properties of the films were studied by positron life time spectroscopy (PLTS).