Characterization of Al-Gate MOS Capacitor on Thermally Oxidized 3C/4H Hybrid Polytype-Heterostructure Si-Face SiC(0001) Wafer Fabricated by Simultaneous Lateral Epitaxy (SLE) Method

Abstract:

3C-SiC with a moderate band gap and a large electron affinity is expected to have superior long-term stability against performance degradation. We have fabricated Al-gate MOS diodes in 3C-on-4H-SiC and 4H-SiC regions on a simultaneous lateral epitaxy (SLE) wafer. Here, evaluation results of their high-frequency differential capacitance-voltage (C-V) characteristics are reported and, from suggested band diagrams, carrier transport involved in the phenomena are considered. In the case of n^--type 3C-on-4H-SiC MOS diode, increase in capacitance due to fast modulation in the inversion layer charge (hole) concentration can be confirmed in the negative bias below-5 V. 2-dimensional hole gas (2DHG) is considered at the Si-face 3C/4H heterointerface negatively charged by spontaneous polarization and is expected to be an effective supply source of holes. Especially in the case of p-type 3C-on-4H-SiC MOS diode, it is considered that injection of holes from neutral p-type region into the heterointerface induces compensation of the fixed charges and lowering of the electron barrier at conduction band, and then, electron injection through the barrier causes the fast response of inversion-layer modulation. Appearance of the larger frequency dependence can be understood by inclusion of the larger-activation-energy phenomena, such as “a deep acceptor level” and “2DHG confined by fixed charges”. These findings are believed to contribute to building new production platforms of high-performance power semiconductor devices utilizing the polytype heterostructure of SiC.

• Periodical: Materials Science Forum (Volume 1192)
• Pages: 39-45
• DOI: https://doi.org/10.4028/p-Am6ufR
• Online since: May 2026
• Authors: Masao Sakuraba*, Tatsunori Oki, Satoshi Watanabe, Shigeo Sato, Iori Morita, Tetsuya Ueno, Seima Sato, Hiroyuki Nagasawa, Yukimune Watanabe, Maki Suemitsu
• Keywords: 2-Dimensional Hole Gas (2DHG), 3C-SiC, 4H-SiC, Carrier Transport, Heterointerface, Metal-Oxide-Semiconductor (MOS) Capacitor, Polytype Heterostructure, Spontaneous Polarization

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