Advanced temperature estimation in low Rds,on p-GaN HEMT devices for performing power cycling tests

Inhalt:
A new method for temperature estimation of the channel temperature in p-GaN HEMT devices is presented. The Vds voltage drop of AlGaN/GaN devices with low Rds,on by applied measurement current of 0.1-1 A in power cycling tests is hardly applicable for temperature sensing. The application of higher measurement currents is possible but not appropriate, especially in devices with paralleled chips it is technically challenging. Promising is the use of the remarkable gate leakage current as temperature sensitive electrical parameter (TSEP) due to the Schottky gate structure of these devices. The temperature calibration of the gate leakage current was applied in a power cycling test. A simultaneously applied Rds,on calibration - executed with a sufficient high measurement current - showed nearly the same measurement results and therefore serves as a verification for the accuracy of the test method.