(Ultra)Wide-Bandgap Vertical Power FinFETs
Yuhao Zhang, Tomás Palacios
Abstract
FinFET is the backbone device technology for CMOS electronics at deeply scaled technology nodes per Moore's law. Recently, the FinFET concept has been leveraged to develop a new generation of vertical power transistors based on wide-bandgap (WBG) and ultrawide-bandgap (UWBG) semiconductors for kilovolts and high-power applications. The sidewall gate-stack in a vertical power FinFET can rely on either a metal-oxide-semiconductor (MOS) structure or a p-n junction, rendering a Fin-MOSFET or a fin-based junction field-effect transistor (Fin-JFET), respectively. Although the device technologies are still at the early stage of development, 1.2-kV-class WBG gallium nitride (GaN) power Fin-MOSFETs have demonstrated one of the highest static and switching performances in all similarly rated power transistors; UWBG gallium oxide power Fin-MOSFETs have shown high performance up to a breakdown voltage over 2.6 kV. Early UWBG diamond lateral power Fin-MOSFETs have also been demonstrated. Meanwhile, GaN power Fin-JFETs are currently under active development. This article provides a comprehensive tutorial and review of the background and recent advances in WBG and UWBG vertical power FinFETs. It covers fundamental device physics, device and process development, as well as the static and switching performance of various power Fin-MOSFETs and Fin-JFETs. This article is concluded by identifying the current challenges and exciting research opportunities in this very dynamic research field.