Mutual influence among inert nitrogen molecules, nitrogen radical atoms, nitrogen radical molecules and nitrogen molecular ions on growth process and crystal structure of GaN heteroepitaxial layers grown on Si(0 0 1) and Si(1 1 1) substrates by molecular-beam epitaxy assisted by electron cyclotron resonance

Abstract

We have investigated the mutual influence among inert nitrogen molecules, nitrogen radical atoms, nitrogen radial molecules and nitrogen molecular ions on optical and crystallographic properties of GaN heteroepitaxial layers (heteroepilayers) grown on Si(0 0 1) and Si(1 1 1) substrates by molecular-beam epitaxy assisted by electron cyclotron resonance (ECR). The heteroepilayer characteristics are elementally governed by the effective V/III mole ratio corresponding to the ratio of the density of nitrogen radical molecules in inert nitrogen molecules to Ga atoms in ECR-plasma process. The inert nitrogen molecules in ECR nitrogen plasma do not much degrade the crystalline quality of GaN heteroepilayer though they change the effective V/III mole ratio and dramatically reduce the growth rate. However, the heavy incorporation of inert nitrogen molecules into the layer degrades the crystalline qualities of GaN heteroepilayers.