Recessed p-GaN Gate MIS-HEMT with AlN Interlayer and Buried p-GaN Layer

Herein, the design of a normally off p-GaN metal-insulator-semiconductor high electron mobility transistor (MIS-HEMT) comprising a recessed p-GaN gate and a buried p-GaN back barrier layer is reported. The proposed structure is capable to minimize the trade-off between current output and threshold voltage, which is one of the bottlenecks in the design of efficient enhancement mode high electron mobility transistors (HEMTs). The incorporation of both buried p-GaN layer and recessed p-GaN gate structure simultaneously into the conventional device ensures higher threshold voltage along with better current drive capability. In addition, the use of AlN interlayer enhances the 2DEG density in the proposed structure. The device offers a maximum transconductance of about 191 mS/mm compared to the conventional p-GaN gate enhancement mode HEMT which has a value of 172 mS/mm only. The threshold voltages of the p-GaN gate HEMT and the proposed structure are +0.582 and +1.48 V, respectively.