Transient gate resistance thermometry demonstrated on GaAs and GaN FET

The development of transient gate resistance thermometry (T-GRT) is reported. It is a technique used to measure the transient self-heating of a FET's gate metal. Demonstrations of T-GRT are presented at the wafer level on a GaAs pHEMT and an AlGaN/GaN-on-SiC HEMT. Dynamic self heating is monitored from hundreds of nanoseconds to hundreds of milliseconds. Preliminary finite-element simulations across a range of power dissipation levels agree closely with T-GRT at, and beyond, 1 μs after the applied drain pulse. Characterization of dynamic self heating and its application to pulsed applications such as radar are discussed.