Growth Temperature Dependency of High Al Content AlGaN Epilayers on AlN/Al2O3 Templates

In this work, MOVPE (Metalorganic Vapor Phase Epitaxy) growth and characterization studies of high Al content AlGaN epilayers are reported. We utilize high resolution X-ray diffraction (HRXRD) and atomic force microscope (AFM) techniques to analyze the crystalline quality and surface morphology of AlGaN epilayers. The role of the growth temperature of AlGaN epilayers on the structural quality and the surface morphology was investigated. Growth and measurement results show that single phase AlGaN epilayers were grown on AlN/Al2O3 template. It is concluded that the increasing growth temperature increases the Al content of AlGaN epilayers which enable to control the alloy concentration of AlGaN. Furthermore, the increasing Al content in AlGaN epilayers leads to the smooth surface which indicates that the decreasing number of dislocation density.