EFFECT OF SUBSTRATE BIAS ON SILICON THIN-FILM GROWTH IN PLASMA-ENHANCED CHEMICAL VAPOR-DEPOSITION AT CRYOGENIC TEMPERATURES

The ion irradiation effect on a growing silicon surface in a silane plasma has been studied at a substrate temperature of -110-degrees-C where the thermal reaction is basically quenched. The ion flux and mean energy have been varied by employing a triode reactor in which dc bias is applied to the substrate electrode. It is shown that ion bombardment interrupts the surface polymerization reaction and causes the desorption of deposition precursors. By reducing ion bombardment, the deposition precursors on the surface were liquified, and hence film growth proceeded selectively from the groove bottoms on the fine-patterned surface.