This research concerns the effects of elevated ambient and substrate temperatures (25oC to 400oC or higher) on the terminal characteristics of integrated Silicon Carbide (hexagonal or 6H polytype - SiC) MOS Field-Effect transistors. The work will focus on the detailed experimental and analytical modeling of large and small signal parameters of the transistors, with particular emphasis on leakage currents, on channel mobility, and on temperature- induced threshold voltage shifts with substrate bias.