Influence of 4H-SiC Epitaxial Morphological Defects on the Electrical Characteristics of MOSFET

doi:10.16553/j.cnki.issn1000-985x.2025.0223

Abstract

Abstract: 4H-SiC metal-oxide-semiconductor field-effect transistor （MOSFET） has become one of the most promising semiconductor devices due to their excellent properties such as high breakdown voltage， fast switching， and low loss. However， the yield and reliability of MOSFET can be degraded by morphological defects formed during the epitaxial process. In this study， the influence of three types of morphological defects on the electrical characteristics of 6.5 kV MOSFET was investigated. The results show that triangle defects can lead to early breakdown of the device， with a reverse breakdown voltage not exceeding 3 V. Furthermore， the presence of these defects in the active region also induces gate control failure. In contrast， triangle-like defects and linear defects have no significant impact on the breakdown voltage of the device， but the on-resistance of device with the triangle-like defect increases by 4.56%. Although triangle-like defects exhibit smaller band-gap shrinkage compared to linear defects， they introduce higher localized stress in their morphology and have a stacking fault area five times larger than that of linear defects， resulting in increased on-resistance of the device. In addition， both triangle-like defects and linear defects exhibit leakage current when a negative voltage was applied by the conductive atomic force microscope. Although neither type of defect caused significant changes in the static characteristics of the device， this behavior remains detrimental to long-term reliability.

Key words: 4H-SiC; MOSFET; epitaxial morphological defect; electrical characteristic; breakdown voltage; on-resistance

CLC Number:

WANG Pin, WANG Jing, LIU Decai, ZHANG Wenting, YU Le, LI Zheyang. Influence of 4H-SiC Epitaxial Morphological Defects on the Electrical Characteristics of MOSFET[J]. Journal of Synthetic Crystals, 2026, 55(3): 387-394.

Figures/Tables 8

Fig.1 Scatter， Vis-PL， and topography channels images of morphological defects

Fig.2 Optical microscopy （OM） images and characteristics of MOSFETs with triangle defects. （a） OM image of the triangle defect located in the active region；（b） OM image of the triangle defect in the termination region；（c） reverse I-V characteristics of devices；（d） I-V characteristics of the internal body diode

Fig.3 Characteristics comparison of MOSFETs with triangle-like defects and linear defects. （a） Reverse I-V characteristics for devices；（b） transfer characteristics for devices with/without triangle-like defects；（c） transfer characteristics for devices with/without linear defects；（d） on-state resistance （Ron） of devices

Fig.4 OM images and height profiles of the triangle-like defect and linear defect

Fig.5 Three-dimensional overlay plots of height and leakage current of the triangle-like defect （a） and the linear defect （b）

Fig.6 PL spectra of the triangle-like defect and the linear defect

Fig.7 Raman spectra of the triangle-like defect and the linear defect

Fig.8 OM images and Raman mapping images of the triangle-like defect （a） and the linear defect （b）

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