Papers by Author: Satomi Itoh

Abstract: Characteristics of SiC MOSFETs and SBDs with 3.3 kV-class have been presented. Static Characteristics of the MOSFET showed a specific on-resistance of 14.2 mΩ cm². A breakdown voltage of 3850 V is obtained by using the dose optimized edge termination structure as we have previously reported [1]. At the same time, reverse leakage current of the 3.3 kV SiC SBDs can be suppressed by the JBS structure and the edge termination which is also used in the MOSFETs. By using the MOSFETs and SBDs, we have demonstrated the superior capability of the 3.3 kV 400 A full SiC 2 in 1 modules with a compatible case and terminal configurations to Si IGBT modules. Dynamic characteristics of the full SiC module in an inductive load switching exhibits superior turn-on and turn-off properties even at a high drain voltage of 1650 V, demonstrating the availability of high voltage SiC power systems.

Abstract: Polyethylene (PE) substrates were irradiated at a dose of 1×1015 ions·cm−2 by the simultaneous use of oxygen (O2) cluster and monomer ion beams. The acceleration voltage for the ion beams was 7 kV. Unirradiated and irradiated PE substrates were soaked in simulated body fluid with ion concentrations 1.5 times of those of human blood plasma (1.5SBF) for 7 days. The irradiated PE substrate formed apatite on its surface, whereas unirradiated one did not form it. This is attributed to the formation of functional groups effective for apatite nucleation, such as COOH groups, on the substrate surface by the simultaneous use of O2 cluster and monomer ion beams. In addition, the apatite-forming ability of the irradiated substrate was improved by the subsequent CaCl2 treatment. This suggests that Ca2+ ions present on the substrate surface accelerated the apatite deposition. We can conclude that apatite-forming ability can be induced on surface of polyethylene by the simultaneous use of O2 cluster and monomer ion beams.