Reverse Blocking GaN High Electron Mobility Transistors with Stepped P-GaN Drain

Abstract

In this work, a reverse-blocking high electron mobility transistor with stepped p-type GaN drain (SPD RB-HEMT) has been proposed and studied in TCAD Sentaurus. In SPD RB-HEMT, the reverse-blocking capability is achieved by employing a stepped p-type GaN (P-GaN) layer connected with the Schottky metal drain. The stepped P-GaN layer is constituted by four P-GaN steps, and the thicknesses of the first to the fourth P-GaN step are descending from the source to the drain side. Due to the P-GaN/AlGaN/GaN structure, the conduction band of the AlGaN/GaN interface is lifted up. Therefore, the two-dimensional electron gas (2-DEG) channel is depleted, and the reverse current is blocked. On the other hand, when the drain is forward biased, the 2-DEG channel is recovered, and the drain induced barrier lowering (DIBL) effect in stepped P-GaN drain structure can lead to a lower on-resistance of the device. The SPD RB-HEMT exhibits a reverse breakdown voltage of −2209 V and on-resistance of 3.01 mΩ·cm2 in TCAD Sentaurus simulation. Compared with the conventional Schottky barrier drain and planar P-GaN drain RB-HEMTs, the SPD RB-HEMTs have shown the balanced and improved forward and reverse-blocking characteristics.