Optically Controlled Vertical GaN finFET for Power Applications

Abstract

With the increasing demand for electricity, efficient power electronics with high voltage and current capabilities become crucial in many applications. However, current power devices are mostly electrically triggered. Multilevel converters made of such devices often require complicated gate-driving circuits and are susceptible to electromagnetic interference (EMI). Optically triggered power devices can significantly improve circuit complexity, EMI susceptibility, and system reliability.

This thesis presents the first demonstration of an optically controlled vertical GaN finFET. The first part of the thesis describes the physics and design of the device assisted by simulation, followed by the fabrication using a Design-Technology Co-Optimization (DTCO) approach. Finally, device measurements are presented. Our devices have shown a maximum current density of J subscript DS > 90A/cm² at V subscript DS = 3 V, triggered by a low-power 365nm LED, which translates into optical responsivity greater than 10⁵A/W. These preliminary results have shown promising aspects of our devices to enable future high voltage, high current power systems.