Investigation of carrier gas on morphological and structural characteristics of AlGaN/GaN HEMT

Abstract

In this study, the effect of carrier gas (H2 and N2) on the AlGaN barrier layer of AlGaN/GaN High Electron Mobility Transistor (HEMT) epi-structures has been investigated in terms of its morphological and structural characteristics. The epi-structures have been grown on a 4H-SiC substrate by Metal Organic Vapor Phase Epitaxy (MOVPE). Morphological, crystalline, and interfacial quality of the AlGaN barrier layer has been significantly improved by using a nitrogen carrier gas. The effect of an improved barrier layer on 2DEG (Two-Dimensional Electron Gas) transport properties of HEMT epi‑structure has also been studied. The improved interface resulted in excellent 2DEG transport properties (mobility of 2060 cm2/V·s with 1 × 1013 cm−2 concentration) of HEMT epi-structure. It was also observed that growth rate and carbon incorporation in the GaN layer reduced with the use of nitrogen carrier gas.