GaN Electronics for High-Temperature Applications

Abstract

Gallium nitride is a promising candidate for harsh environment electronics, thanks to its excellent material properties, which have given rise to high-performance (room temperature) transistors for RF, power, MEMS, and mixed-signal applications. Previous works on high-temperature (HT) electronics have been typically limited to two aspects, namely, the high-temperature robustness of discrete transistors and basic circuit building blocks, which are mainly combinational logic. While these studies offer a strong indication of the potential of GaN transistor technology for HT applications, the development of HT (500 °C) GaN-ICs is still at its early stage due to the low degree of complexity and integration demonstrated so far. Major challenges in the realization of GaN HT-robust sequential logic circuits or more complex systems is the lack of a scalable technology.

This thesis aims to advance the integration technology of GaN HT electronics by demonstrating a comprehensive HT (500°C) enhancement-mode (E-mode) GaN-on-Si technology from device to circuit perspectives: (1) a scalable device technology based on p-GaN-gate AlGaN/GaN HEMTs with high uniformity, which is optimized for HT operation and demonstrated to offer robust performance at least up to 500 °C with the help of in-house developed packaging technology and characterization platform, (2) compact modeling of monolithically integrated enhancement/depletion-mode HEMTs up to 500 °C HEMTs, (3) robustness-driven circuit design based on GaN technology, (4) demonstration of GaN-based combinational and sequential building blocks including inverter, NAND, NOR, ring oscillators, ROM, SRAM, D Latch, D Flip-Flop operational up to 500 °C.