A screening test of GaN-HEMTs for improvement of breakdown voltage uniformity

As a screening test recipe, burst unclamped inductive switching (UIS) test is proposed to improve breakdown voltage uniformity. One of the critical disadvantages of GaN-HEMTs is its lack of the UIS withstanding capability, because there is no removal structure of holes, which generated by the avalanche breakdown. Hence, at the screening in the mass-production, measurement of the avalanche breakdown voltage cannot be employed to reject low breakdown voltage devices due to catastrophic failure, and conventional static drain leakage current measurements are insufficient. This paper reports a screening test of GaN-HEMTs by repetitive overvoltage stress using burst UIS test. The experimental results show the repetitive overvoltage stress was needed to reject outliers with low breakdown voltage and optimum test current avoided to generate new outliers.