Thermal analysis of GaN-on-SiC HEMTs with different backside via layouts

Temperature dependent electrical characteristics of GaN-on-SiC high-electron mobility transistors (HEMTs) with different backsides via layouts are presented. AlGaN/GaN HEMTs with outside backside via (OSV) and internal backside via (ISV) were processed with the same device geometry on the same wafer. HEMTs with ISV layout show a lower thermal resistance because of an extra via at the center of device. Comparisons of the device characteristics of HEMTs with OSV and ISV layouts including threshold voltage, on-resistance, and source resistance (extracted from DC measurements) and drain resistance, gate-source capacitance, gate-drain capacitance, and drain-source capacitance (extracted from RF measurements) are discussed at different temperatures. Moreover, pulsed measurements confirmed that the difference in drain current from DC measurement due to self-heating is less in the ISV layout.