Application of electron cyclotron resonance chemical vapour deposition in the preparation of hydrogenated boron-doped Sic films

Abstract

Hydrogenated silicon carbide (Sic: H) films were deposited using the electron cyclotron resonance (ECR) chemical vapour deposition (CVD) technique from a mixture of methane, silane and hydrogen using diborane as the doping gas. The effects of changes in the microwave power on the deposition rate and optical bandgap were investigated, and variations in the photoconductivity and dark conductivity and activation energy were studied in conjunction with film analysis using the Raman scattering technique. The conductivity increased rapidly to a maximum, followed by rapid reduction at high microwave powers. The ratio ([sgrave]_ph/[sgrave]_d) of the photoconductivity to the dark conductivity peaked at microwave power of about 600 W. Under conditions of high microwave power, Raman scattering analysis showed evidence of the formation and increase in the silicon microcrystalline and diamond-like phases in the films, the former of which could account for the rapid increase and the latter the subsequent decrease in the conductivity. A comparison between the effects of boron doping reprinted in this paper and phosphorus doping reported in our earlier work will be made.