GaN smart power chip technology

Abstract

Wide-bandgap GaN-based semiconductor materials are attracting considerable attention as the preferred material for power electronics applications, owning to their superior properties including high breakdown electric-field, high carrier density, high electron mobility and high saturation velocity. In this paper, the technologies for implementing GaN smart power ICs will be introduced based on the large-size, low-cost and highly scalable GaN-on-Si platform. High-voltage power components (normally-off power transistors and HEMT-compatible rectifiers) and low-voltage periphery devices for digital/analog mixed-signal circuits are successfully integrated with the same fabrication process. In particular, key analog functional blocks such as voltage reference generators and comparators are demonstrated using GaN-based technology for the first time. The optimized voltage reference generator achieved less than 70 ppm/°C drift and can be used as a reference voltage in various biasing and sensing circuits. The temperature-dependent performance of a conventional comparator is characterized and a new temperature-compensated comparator circuit is also demonstrated. The positive limiting level of the temperature-compensated comparator is less than 450 ppm/°C drift compared to 1400 ppm/°C in the conventional comparator.