Direct current characterization of depletion-mode 6H-SiC mosfets from 294 to 723 K

6H-SiC depletion-mode, n-channel MOSFETs were analyzed across the temperature range of 295-723 K. Effective channel mobilities ranged from 94 cm(2) V-1. s(-1) at 296 K to about 20 cm(2) V-1. s(-1) in the five devices measured. Small-signal voltage gain ranged from 5 V/V to 20 V/V in the five devices tested, and was essentially constant for all devices up to 723 K. Thermally-activated leakage across the 450 Angstrom thick gate oxide (SiO2) was identified as the primary cause of device failure from 673 to 773 K. The mechanisms responsible for the leakage across SiO2 were identified as Fowler-Nordheim tunneling at bias levels greater than about 650 kV cm(-1), while low-field leakage was a result of trap-assisted tunneling in combination with other mechanisms such as Poole-Frenkel or thermionic emission. Measured source-drain to body (pn junction) leakage was thermally activated with an activation energy of approximately 972 meV.