Advances and Perspectives in Gate Dielectric Thin Films for 4H-SiC MOSFETs

TL;DR

This paper reviews recent advances in gate dielectric materials for 4H-SiC MOSFETs, focusing on improving performance and reliability through material engineering.

Contribution

The paper systematically reviews and compares SiO2-based and high-k gate dielectrics, highlighting their impact on interface properties and device performance.

Findings

Interface nitridation and surface pretreatment significantly reduce carbon-related defects in SiO2/SiC systems.

High-k dielectrics like Al2O3 and HfO2 improve gate capacitance and reduce leakage current in SiC MOSFETs.

Stacked dielectric structures and in situ interface engineering show promise for enhancing device reliability and mobility.

Abstract

The performance and reliability of 4H-SiC Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) are largely determined by the material properties of gate dielectric films and the quality of the dielectric/SiC interface. This paper provides a systematic review of recent progress in gate dielectric engineering for 4H-SiC MOSFETs, with emphasis on SiO2-based gate dielectrics and high-dielectric-constant (high-k) gate dielectrics. First, for conventional thermally grown SiO2/SiC systems, the effects of interface nitridation, gate oxide doping, and surface pretreatment techniques are comprehensively discussed. The influence mechanisms of these processes on carbon-related interface defects, interface state density and field-effect mobility are analyzed, and the advances in related research are summarized. Second, the application of high-k gate dielectrics, including Al2O3, HfO2, ZrO2, and stacked dielectric structures, in SiC MOS devices is systematically reviewed. The advantages of these materials in reducing equivalent oxide thickness, increasing gate capacitance, suppressing leakage current, and improving thermal stability are highlighted. In addition, interface defects and electrical characteristics associated with different high-k gate dielectrics are comparatively evaluated. Finally, future research directions are discussed, including in situ interface engineering based on atomic layer deposition, dopant modulation, and heterogeneous gate dielectric structures. These approaches show strong potential for achieving high mobility, low loss, and high reliability in advanced 4H-SiC power MOSFETs.

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