High-temperature performance of AlGaN/GaN HFETs and MOSHFETs

Performance of AlGaN/GaN HFETs and Al2O3/AlGaN/GaN MOSHFETs at the elevated temperatures up to 425 °C was investigated. Static output and transfer characteristics were measured and the saturation drain current, the peak transconductance and the series conductance as a function of temperature were evaluated. All these characteristic features of HFETs and MOSHFETs decreased with increased temperature. At 425 °C the devices exhibited ∼30% of their saturation drain current, peak transconductance and series conductance evaluated at room temperature. The device performance at elevated temperatures follows exactly the Tx dependence with a power x = −1.5. This indicates that the temperature dependence of the mobility of channel electrons due to phonon scattering is the predominant effect describing high-temperature performance of AlGaN/GaN HFETs and MOSHFETs.