Compositional analysis of In-rich InGaN layers grown on GaN templates by metalorganic chemical vapor deposition

Abstract

In-rich InGaN layers were successfully grown on GaN templates by metalorganic chemical vapor deposition. In incorporation in InGaN layer was enhanced by decreasing the growth temperature, and In-rich InGaN layer with In content higher than 70% was obtained below 670 °C. Especially, double peaks from In-rich InGaN grown at 640 °C appeared in X-ray diffraction pattern and photoluminescence (PL). The further investigation of strain status of InGaN layers by reciprocal space mapping (RSM) clarified that In-rich InGaN layers were fully relaxed and consisted of InGaN alloys of two different In contents of 82% and 97%, respectively. As a result, we confirmed that compositional inhomogeneity which is mainly reported in Ga-rich InGaN layer could exist in In-rich InGaN layer higher than 80%. We also investigated In incorporation behavior in InGaN at low temperature (640 °C). In content in InGaN layer was found to be controlled by just changing input gas phase mole fraction (TMIn/(TMGa+TMIn)) at low growth temperature and a linear relationship was observed between In content in InGaN layers and gas phase mole fraction.