Investigation of initial growth process for GaN heteroepitaxial layers grown on Si(001) and Si(111) substrates by ECR-assisted MBE

摘要

High luminescence efficiency zincblende-GaN (β-GaN) crystal islands were preferentially grown on Si at initial growth process, particularly on non-pretreated (001)-oriented Si. The initial growth process was strongly influenced by substrate treatment before growth, namely substrate surface state. It was confirmed by a high-resolution cross-sectional transmission electron microscopy that both wurtzite- and β-GaN crystal grains were epitaxially grown by mixing in the plane on a 2.5nm-thick amorphous SiN_X interface layer, which was instantly formed within 10s during substrate nitridation or/and initial growth process.