Device characterization of gallium nitride high electron mobility transistor with a boron nitride heat-spreading element

A local thermal management solution for high electron mobility transistors based on GaN was developed using a BN layer as a heat-spreading element. The thermally conducting and electrically insulating nature of BN allows it to be placed close to the active area and to be in direct contact with the electrodes and the heat sink, thus introducing an additional heat-escaping route. The numerical simulations of a GaN high electron mobility transistor with the BN heat-spreading element revealed the improvement in the DC, breakdown, small-signal AC and transient characteristics. In case of sapphire substrate, the maximum temperature in the device structure operating at a power density of 3.3 W/mm was reduced by 82.4 °C, while the breakdown voltage at a gate-source voltage of 2 V was increased by 357 V. The cut-off frequency and the maximum oscillation frequency at a gate-source voltage of 6 V and a drain-source voltage of 30 V were enhanced by 1.38 and 1.49 times, respectively. We suppose that the proposed thermal management method can be adapted to other high-power devices.