Characterization of Large Area 4H-SiC and 6H-SiC Capacitive Devices at 600 °C

SiC based capacitive devices have the potential to operate in high temperature, chemically corrosive environments provided that the electrical integrity of the gate oxide and metallization can be maintained in these environments. We report on the performance of large area, up to 8 x 10-3 cm2, field-effect capacitive sensors fabricated on both the 4H and 6H polytypes at 600°C. Large area capacitors improve the signal/noise (S/N) ratio which is proportional to the slope of the capacitance-voltage characteristic. At 600 °C we obtain a S/N ~ 20. The device response is independent of polytype, either 4H or 6H-SiC. These results demonstrate the reliability of our field-effect structure, operating as a simple potentiometer at high temperature.