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Ultrahigh voltage SiC bipolar devices more than 13 kV were developed, and their package technology was investigated. As a result, we have succeeded in creating a 13kV level PiN diode without forward voltage degradation by using 4° off substrates and a 15kV p-channel IGBT with a low differential specific on-resistance (R diff,on ) at high temperature. Moreover, the results reveal that the nano-tech resin, improved resin and Si 3 N 4 DBC substrate are the best materials for package at high temperature and ultrahigh voltage.

We successfully fabricated 13-kV, 20-A, 8 mm × 8 mm, drift-free 4H-SiC PiN diodes. The fabricated diodes exhibited breakdown voltages that exceeded 13 kV, a forward voltage drop of 4.9–5.3 V, and an on-resistance (RonAactive) of 12 mW·cm2. The blocking yield at 10 kV on a 3-in wafer exceeded 90%. We investigated failed devices using Candela defect maps and light-emission images and found that a few devices failed because of large defects on the chip. We also demonstrated that the fabricated diodes can be used in conducting high-voltage and high-current switching tests.

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Techniques for measuring hydrogen (H 2) and methane (CH 4) levels in breaths were assessed in horses with gastrointestinal (GI) diseases. A total of 31 horses were studied: 11 healthy horses (Group A), 10 horses with GI diseases (Group B), and 10 horses with diseases without GI involvement (Group C). Expired gases were measured using gas chromatography. CH 4 levels in Group A were significantly lower than those in Group B. In Group B, CH 4 levels were significantly higher after treatment. Fluctuations in H 2 and CH 4 levels in breath were associated with changes in GI function.