2000 Fiscal Year Final Research Report Summary
Control of Electronic Properties of Wide Bandgap Semiconductor and Application to Energy Electronics
| Project/Area Number |
09102009
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| Research Category |
Grant-in-Aid for Specially Promoted Research
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| Allocation Type | Single-year Grants |
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| Review Section |
Physics
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
MATSUNAMI Hiroyuki Kyoto University, Graduate School of Eng., Professor, 工学研究科, 教授 (50026035)
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| Co-Investigator(Kenkyū-buntansha) |
KIMOTO Tsunenobu Kyoto University, Graduate School of Eng., Associate Professor, 工学研究科, 助教授 (80225078)
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| Project Period (FY) |
1997 – 2000
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| Keywords | silicon carbide / power device / pn diode / MOSFET / ion implantation / thermal oxidation |
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| Research Abstract |
In this research project, high-quality epitaxial growth of wide bandgap SiC, control of its properties and MOS (metal-oxide-semiconductor) interfaces, and applications to high-power devices have been investigated. By using high-purity and high-quality SiC epilayers, conductivity control has been realized in the wide range from 10^<14> to 10^<20>cm^<-3>. Selective impurity doping by ion implantation has been systematically investigated. Low sheet resistances of 105Ω/□ for n-type and 3600Ω/□ for p-type were obtained. Formation of deep pn junction by MeV ion implantation and semi-insulating SiC layers formed by V ion implantation were also investigated.
Detailed characterization of MOS capacitors on n- and p-type SiC revealed clear relationship between oxidation condition and MOS interface quality. The inversion channel mobility in SiC MOSFETs may be controlled by the electron trapping and negative charge caused by shallow acceptor-like interface states. The channel mobility has been improved from 5cm^2/Vs up to 96cm^2/Vs by utilizing a novel crystal face of (1120). The channel mobility for SiC (1120) MOSFETs showed a negative temperature coefficient for the first time, which is critical for power MOSFET applications.
Various high-voltage SiC devices have been successfully fabricated. Ni/SiC Schottky diodes exhibited a 1630V breakdown voltage together with a low on-resistance of 5mΩcm^2. Epitaxial mesa and implanted planar SiC pin diodes showed very high breakdown voltages of 4200V and 4600V, respectively. The breakdown voltages of SiC pin diodes increased with increasing temperature, indicating avalanche breakdown. Lateral high-voltage (700V) SiC MOSFETs have been also demonstrated.
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Research Products
(14 results)
