Thermal transient characterization of pHEMT devices

In this paper the issues of thermal transient measurement of heterostructure field-effect transistors are discussed. It is shown that the measurement setups used for MOSFET devices may produce artifacts. Even though the measured transients may seem to be thermal, at the calibration of the measured temperature sensitive parameter no temperature dependency is observed. The influence of the gatelag effect is discussed, which is a plausible reason of the electric transients with a time constant in a few millisecond range. Finally a practical measurement setup is presented utilizing the forward voltage of the Schottky barrier gate as a temperature sensitive parameter.