Metalorganic Vapor Phase Epitaxy of Thick InGaN on Sapphire Substrate

Growth of thick InGaN films was performed on single crystal films of GaN or AlGaN and buffer layers of AlN, GaN or AlGaN by metalorganic vapor phase epitaxy (MOVPE). In the growth of InGaN on GaN or AlGaN films, smooth InGaN films with small indium mole fractions were grown in the initial growth stage caused by strong stress due to lattice mismatch. However, with an increase in thickness of the InGaN film surface became rough due to the generation of InGaN grains with large indium mole fractions. Smooth and thick (∼2 µ m) InGaN films with large indium mole fractions were grown on AlN, GaN or AlGaN buffer layers.