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内容記述 |
High temperature operation of MOSFETs are requested for electronics in the automotive, various on-engine aerospace electronics systems, and power industries. Silicon carbide (4H-SiC) has a wider bandgap and higher thermal conductivity than silicon, however, at the high temperature, degradation and breakdown are induced in metal wires and gate electrodes, because Al and Cu wires easily melt or oxidized. In this study, 4H-SiC n or p channel MOSFETs with Pt/Ti and Pt/TiN wires were fabricated by attaching tiranium (Ti) and titanium nitride (TiN) adhesion layer and their operation under high temperature was investigated. After exposure to 500 degrees for 10 hours, drain current -drain voltage (ID-VD) characteristics at 500 degrees for n channel SiC MOSFET showed a decreased current in the saturation region. For the p channel MOSFET, large drain current flows below the threshold voltage. These suggested degradation of ohmic contact due to high temperature and the substrate current due to impact ionization. Threshold voltage decreases with increasing temperature regardless of the adhesion layer type. After cooling to room temperature, it decreased compared with that before heating. Although mobility was also decreased, MOSFET with TiN adhesion layer showed less degradation. |
