Raman Scattering Method to Measure and Improve the GaN Epitaxial layer of HEMT

In this work, a method of analyzing the crystal quality of epitaxial GaN by Raman spectroscopy was established. An AlN layer was deposited on sapphire substrate by sputtering and an AlGaN/GaN HEMT device is fabricated. The relationship between the dislocation density of GaN with/without AlN layer and the electrical performance was studied.