Mitigation of self-heating in AlGaN/GaN HEMTs using transferred LPCVD-grown h-BN
Cheng Chang, Kad Dokwan Kook, Chenyang Lin, Xiang Zhang, Yuetong Yang, Shisong Luo, Ziyi He, Tao Li, Mingfei Xu, Lucas Lau, Md Jahidul Hoq Emon, Rummanur Rahad, Pulickel M. Ajayan, Jun Lou, Satish Kumar, Yuji Zhao
Abstract
With the increasing power density of GaN-based power devices, the self-heating effect has become a significant bottleneck, impacting device reliability and performance, which makes effective thermal management essential. Hexagonal boron nitride (h-BN), with its high thermal conductivity and excellent electrical insulation, offers a promising solution for heat dissipation. In this Letter, we demonstrate that the transferred low-pressure chemical vapor deposition-grown h-BN effectively mitigates self-heating in AlGaN/gallium nitride high electron mobility transistors. All 12 tested devices showed increased current after BN transfer. The average current density in the saturation region improved from 819 to 924 mA/mm, and the current retention rose from 89% to 98%. Thermo-reflectance measurements revealed a significant reduction in channel temperature from 179 to 115 °C under a power density of 21 W/mm. The improvement is attributed to the high in-plane thermal conductivity of h-BN, which is proven by the hotspot models. This approach shows promise as a practical method to reduce self-heating and enhance the thermal reliability of GaN-based power transistors.