Demonstration and thermal reliability of an e-mode p-type hexagonal boron nitride gate AlGaN/GaN HEMT

Abstract In this letter, we demonstrate an enhancement AlGaN/GaN HEMT with a p-type hexagonal boron nitride (hBN) gate. A major benefit of such a structure is that hBN has a larger bandgap and critical electric field than GaN, hence the proposed device exhibits a larger threshold voltage and gate breakdown compared with the conventional p-GaN gate AlGaN/GaN HEMT. In addition, diagrams of p-hBN/AlGaN/GaN heterojunctions can be regulated by a higher Schottky barrier height with a p-hBN gate, leading to a better output performance. Moreover, better thermal reliability is obtained by the p-hBN gate device with smaller differences in electrical characteristics between room temperature (300 K) and substrate temperature of 320 K. This can be ascribed to the larger thermal conductivity of hBN, resulting in a much lower temperature in the channel.