Growth model for plasma-assisted molecular beam epitaxy of N-polar and Ga-polar InxGa1−xN

Abstract

The authors have developed a comprehensive model for the growth of N-polar and Ga-polar InxGa1−xN by N2 plasma-assisted molecular beam epitaxy. GaN films of both polarities were coloaded and InxGa1−xN was grown in the composition range of 0.14<x<0.59 at different growth temperatures keeping all other conditions identical. The compositions were estimated by triple-axis ω-2θ x-ray diffraction scans as well as by room temperature photoluminescence measurements. The dependence of the In composition x in InxGa1−xN on growth temperature and the flux of incoming atomic species is explained using a comprehensive growth model which incorporates desorption of atomic fluxes as well as decomposition of InN component of InxGa1−xN. The model was found to be in good agreement with the experimental data for InxGa1−xN of both polarities. A N-polar In0.31Ga0.69N/In0.05Ga0.95N multi-quantum-well structure grown with conditions predicted by our growth model was found to match the compositions of the active layers well besides achieving a smooth surface morphology at the quantum-well/barrier interface. The understanding of growth kinetics presented here will guide the growth of InxGa1−xN for various device applications in a wide range of growth conditions.