High thermally conductive and electrically insulating 2D boron nitride nanosheet for efficient heat dissipation of high-power transistors

High-power transistors suffer greatly from inefficient heat dissipation of the hotspots, which elevate the local temperature and significantly degrade the performance and reliability of the high-power devices. Although various thermal management methods at package-level have been demonstrated, the heat dissipation from non-uniform hotspots at micro/nanoscale still persist in the high power transistors. Here, we develop a method for local thermal management using thermally conductive and electrical insulating few-layer hexagonal boron nitride (h-BN) as heat spreaders and thick counterpart as heat sinks. The electrically insulating characteristic of h-BN nanosheet allows it to be intimately contacted with the hotspot region that is located at the gate electrode edge near the drain side of a high-electron-mobility transistor (HEMT). The high thermal conductivity of h-BN nanosheet, which is quantitatively measured by Raman thermography, reduces the temperature of the hotspot by introducing an additional heat transporting pathway. Our DC and radio-frequency characterizations of the HEMT show the improvement of saturation current, cut-off frequency and maximum oscillation frequency. The finite element simulations show a temperature decrease of ∼32°C at the hotspot with the use of h-BN nanosheet. This method can be further extended for the micro/nanoscale thermal management of other high-power devices.