Effects of Nitrogen on the Interface Density of States Distribution in 4H-SiC Metal Oxide Semiconductor Field Effect Transistors: Super-hyperfine Interactions and Near Interface Silicon Vacancy Energy Levels

Published

November 13, 2018

Author(s)

Mark Anders, Patrick M. Lenahan, Arthur H. Edwards, Peter A. Schultz, Renee M. Van Ginhoven

Abstract

The performance of SiC-based metal-oxide-semiconductor field-effect transistors (MOSFETs) is greatly enhanced by a post oxidation anneal in NO. These anneals greatly improve effective channel mobilities and substantially decrease interface trap densities. In this work, we investigate the effect of NO anneals on the interface density of states though density functional theory calculations and electrically detected magnetic resonance (EDMR) measurements. EDMR measurements on 4H-SiC MOSFETs indicate that NO annealing substantially reduces the density of near interface SiC silicon vacancy centers: it results in a thirty-fold reduction in the EDMR amplitude. The anneal also alters post NO anneal resonance line shapes significantly. EDMR measurements exclusively sensitive to interface traps with near mid-gap energy levels have line shapes relatively unaffected by NO anneals whereas measurements sensitive to defects with energy levels more broadly distributed in the 4H-SiC band gap are significantly altered by the anneals. Using DFT, we show that the observed change in EDMR linewidth and the correlation with energy levels can be explained by nitrogen atoms introduced by the NO annealing substituting into nearby carbon sites of silicon vacancy defects.

Citation

Journal of Applied Physics

Volume

124

Issue

18

Pub Type

Journals

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DOI Link

Keywords

SiC, silicon vacancy, nitrogen, defects, density of states

Citation

Anders, M. , Lenahan, P. , Edwards, A. , Schultz, P. and Van Ginhoven, R. (2018), Effects of Nitrogen on the Interface Density of States Distribution in 4H-SiC Metal Oxide Semiconductor Field Effect Transistors: Super-hyperfine Interactions and Near Interface Silicon Vacancy Energy Levels, Journal of Applied Physics, [online], https://doi.org/10.1063/1.5045668 (Accessed March 13, 2025)