Monomethylsilane as a New Dopant Precursor for n-Type GaN Grown by MOVPE

Abstract

Monomethylsilane (MMSi) is demonstrated as an alternative Si dopant precursor for silane. It is stable in the air and it is in gas phase at room temperature. Si-doped GaN films were grown by metalorganic vapor-phase epitaxy (MOVPE) using MMSi. The electron concentration was controlled linearly with the MMSi flow rate in the range 1 x 10{sup 18} cm{sup -3} to 2 x 10{sup 19} cm{sup -3}. Carbon contamination in the n-type GaN was measured by secondary ion mass spectroscopy (SIMS) and was lower than the detection limit of SIMS (1 x 10{sup 17} cm{sup -3}). The electron mobility was equal to or higher than those obtained from other reported dopant precursors for a given electron concentration. These results indicate that it is a suitable dopant precursor to obtain n-type GaN in high quality and a much safer MOVPE system can be established. (orig.) 6 refs.