Analysis of Dislocation Density for GaN Based HEMTs in Screw Mod

Abstract

Quick response is an important feature in design of optoelectronic cards. So in this study, structural properties of GaN/AlN/AlGaN HEMTs structures grown on sapphire by the chemical vapor adjustment method are analyzed by the X-ray diffraction method. The main property of these kind of materials is that they are resistant to high voltage, temperature, and pressure. Although their performance is worse compared silicon, for forcing limit standards, they present wide research field. In this study, the focus of investigation is dislocation density stemming from lattice mismatch between layers and wafer causing cracks on the surface. In HEMT structure calculation of dislocation density for GaN and AlN represents all structure. High dislocation density for AlN layer is determined because of aggressive behavior of Al element in the structure. Also, quantized GaN layers stop moving of dislocations and prevents surface cracks.