200 degrees C/5 MHz GaN-based gate driver circuits with 1 nF/4.7 omega RC load for high-temperature high-frequency all-GaN IC applications

A GaN-based gate driver circuits have been successfully designed and fabricated using a commercially available 6-inch GaN-on-Si platform. The driver circuits consist of three-stage direct-coupled FET logic (DCFL) inverters featuring monolithically integrated depletion-mode (D-mode) and enhancement-mode (E-mode) high electron mobility transistors (HEMTs). At room temperature (RT), at a supply voltage of 4 V the single-stage DCFL fabricated on the same die exhibits a large gate swing (3.84 V) and large noise margins (logic-low noise margin (NML) of 1.55 V and logic-high noise margin (NMH) of 2.18 V), both of which are desirable for all-GaN IC applications. Meanwhile, the gate driver circuits were characterised up to 200 degrees C on a PCB with a capacitance load of 1 nF in series with 4.7 omega resistance to resemble the load condition. At 200 degrees C, the gate driver circuits function well even at 5 MHz operation frequency. The turn on/off propagation delay and rise/fall time of the gate driver circuits are 5/40 and 22/18 ns, respectively. As far as the authors' knowledge, this is the highest reported operation frequency for GaN-based gate driver circuits under such high temperature, making it very promising for high-temperature high-frequency all-GaN integrated circuit (IC) applications.