Electrically detected magnetic resonance of carbon dangling bonds at the Si-face 4H-SiC/SiO$_2$ interface

TL;DR

This study uses electrically detected magnetic resonance to identify the dominant defect at the SiC/SiO₂ interface in MOSFETs, finding that the carbon dangling bond (P_bC) center explains the observed spectra across different devices.

Contribution

It demonstrates that the P_bC defect is the primary microscopic defect at the SiC/SiO₂ interface in various MOSFETs, based on comparison of experimental and simulated spectra.

Findings

P_bC center is the dominant defect across devices.

EDMR spectra are consistent despite processing differences.

The P_bC defect explains the hyperfine spectra observed.

Abstract

SiC based metal-oxide-semiconductor field-effect transistors (MOSFETs) have gained a significant importance in power electronics applications. However, electrically active defects at the SiC/SiO$_2$ interface degrade the ideal behavior of the devices. The relevant microscopic defects can be identified by electron paramagnetic resonance (EPR) or electrically detected magnetic resonance (EDMR). This helps to decide which changes to the fabrication process will likely lead to further increases of device performance and reliability. EDMR measurements have shown very similar dominant hyperfine (HF) spectra in differently processed MOSFETs although some discrepancies were observed in the measured $g$-factors. Here, the HF spectra measured of different SiC MOSFETs are compared and it is argued that the same dominant defect is present in all devices. A comparison of the data with simulated spectra of the C dangling bond (P$_\textrm{bC}$) center and the silicon vacancy (V$_\textrm{Si}$) demonstrates that the P$_\textrm{bC}$ center is a more suitable candidate to explain the observed HF spectra.