Silicon carbide: A unique platform for metal-oxide-semiconductor physics

Abstract

A sustainable energy future requires power electronics that can enable significantly higher efficiencies in the generation, distribution, and usage of electrical energy. Silicon carbide (4H-SiC) is one of the most technologically advanced wide bandgap semiconductor that can outperform conventional silicon in terms of power handling, maximum operating temperature, and power conversion efficiency in power modules. While SiC Schottky diode is a mature technology, SiC power Metal Oxide Semiconductor Field Effect Transistors are relatively novel and there is large room for performance improvement. Specifically, major initiatives are under way to improve the inversion channel mobility and gate oxide stability in order to further reduce the on-resistance and enhance the gate reliability. Both problems relate to the defects near the SiO2/SiC interface, which have been the focus of intensive studies for more than a decade. Here we review research on the SiC MOS physics and technology, including its brief history, the state-of-art, and the latest progress in this field. We focus on the two main scientific problems, namely, low channel mobility and bias temperature instability. The possible mechanisms behind these issues are discussed at the device physics level as well as the atomic scale, with the support of published physical analysis and theoretical studies results. Some of the most exciting recent progress in interface engineering for improving the channel mobility and fundamental understanding of channel transport is reviewed.

Ultrawide‐Bandgap Semiconductors: Research Opportunities and Challenges

“…For example, SiC/SiO 2 MOSFETs have suffered from poor channel mobility and threshold voltage stability, due primarily to issues with defects at the SiC/ SiO 2 interface. [186] Similar issues are expected for the UWBG semiconductors; indeed, the issues are expected to be more severe, both for epitaxial and non-epitaxial insulators. For confinement by epitaxial insulators, trapping effects associated with gate insulators have been documented numerous times for power HEMTs based on the epitaxially "simplest" AlGaN/GaN interface, and are at present a significant area of study in the reliability physics community.…”

Review—Ultra-Wide-Bandgap AlGaN Power Electronic Devices

“…8 Recent reports indicate that good progress has been made in solving these problems, at least in isolation. 9 Oxide-less devices such as JFETs circumvent these problems, but such devices typically operate in the normallyon configuration;…”

Performance and Reliability of SiC Power MOSFETs

“…It is also possible that other effects are present which raise the field-effect mobility, such as a high dielectric constant oxide near the interface (such as a thin barium silicate layer), or other effects which change the interface fields. For a comprehensive review of MOS-related issues in SiC, see the recent publication of Liu et al [14].…”