Heavily P-doped (≥1021 cm-3) Si and SiGe films grown by photo-CVD at 250° C

Abstract

A novel photo-CVD process has been successfully applied to a low-temperature heavy-doping technique using SiH4 + SiH2F2 + H2 or SiH4 + SiH2F2 + GeH4 + H2 gas mixture at a very low-temperature of 250° C with PH3 as a doping gas. A maximum electron concentration of 2.3 × 1021 cm-3 and 1.3 × 1021 cm-3 was achieved for Si and Si0.9Ge0.1 epitaxial layer on a single-crystal silicon substrate. The resistivity of the sample monotonously decreased with decreasing the sample temperature, which implies that the carriers were not frozen out in low temperature regions (4K) and that the obtained samples were “metallic” semiconductors.