Silicon Carbide Vertical JFET Operating at High Temperature

Abstract

Trenched and implanted vertical JFETs (TI-VJFETs) with blocking voltages of 700 V were fabricated on commercial 4H-SiC epitaxial wafers. Vertical p+-n junctions were formed by aluminium implantation in sidewalls of strip-like mesa structures. Normally-on 4H-SiC TI-VJFETs had specific on-state resistance (RO-S ) of 8 mW×cm2 measured at room temperature. These devices operated reversibly at a current density of 100 A/cm2 whilst placed on a hot stage at temperature of 500 °C and without any protective atmosphere. The change of RO-S with temperature rising from 20 to 500 °C followed a power law (~ T 2.4) which is close to the temperature dependence of electron mobility in 4H-SiC.