ELECTRICAL-PROPERTIES OF HIGH-RESISTIVITY 6H-SIC UNDER HIGH TEMPERATURE HIGH FIELD STRESS/

The influence of ambient temperature and applied electric field on the electrical properties of high resistivity (1-30 k Omega cm), semi-ins ulating (>100 k Omega cm), and insulating (10(11)-10(12)Omega cm) sing le-crystal 6H-SiC is reported. Current-voltage (I-V) characteristics o f lateral metal-semiconductor-metal test structures were measured in v acuum in a temperature range of 295-730 K and under moderate pulsed el ectric fields (0.5-80 kV/cm). It is shown that the resistivity of the undoped 6H-SiC varies strongly with the ambient temperature after a te mperature/field function dominated by a factor containing the activati on (ionization) energy of residual boron of 0.35 eV. The dominant acti vation energy of semi-insulating Vanadium-compensated material (6H-SiC :V) varies with the ambient temperature, increasing from similar to 0 eV at 295-320 K to similar to 0.8 eV at T greater than or equal to 600 K. This result can explain the relatively low decrease of the resisti vity of insulating 6H-SiC at very high ambient temperatures and its vi ability as a substrate for next-generation high temperature microwave integrated circuits based on large band gap semiconductors. (C) 1997 A merican Institute of Physics.