High-Capacitance-Density ${p}$ -GaN Gate Capacitors for High-Frequency Power Integration

The p-GaN gate capacitors with a metal/p-GaN/AlGaN/GaN structure are demonstrated on an enhancement-mode (E-mode) GaN-on-Si power device platform. High capacitance density of >170 nF/cm
²
is obtained with an operating voltage range of 0 ~ 7 V. Frequency response of the p-GaN gate capacitors with circular and interdigitated layout design are characterized. It is found that the interdigitated layout can suppress the distribution effect and reduce the equivalent series resistance, and thus can significantly enhance the capacitor's high-frequency performance. The fabrication process of the p-GaN gate capacitors is fully compatible with the E-mode GaN power transistors, and thus can be seamlessly implemented as one of the on-chip peripheral components for GaN-based power integrated circuits.