1.2 kV SiC buried grid junction barrier Schottky (BG-JBS) diodes are demonstrated. The design considerations for high temperature applications are investigated. The design is optimized in terms of doping concentration and thickness of the epilayers, as well as grid size and spacing dimensions, in order to obtain low on-resistance and reasonable leakage current even at high temperatures. The device behavior at temperatures ranging from 25 to 250ºC is analyzed and measured on wafer level. The forward voltage drop of 1.1 V at 100 A/cm2 and 3.8 V at 1000 A/cm2 is measured, respectively. At reverse voltage of 1 kV, a leakage current density below 0.1 μA/cm2 and below 0.1 mA/cm2 is measured at 25 and 250ºC, respectively. This proves the effective shielding effect of the BG-JBS design and provides benefits in high voltage applications, particularly for high temperature operation.