Thermal transient test of GaN HEMT devices

In this paper, Thermal Transient Test of GaN HEMT devices is presented. Wide bandgap semiconductors are known to have the advantages such as high breakdown voltage, low resistance, high thermal conductivity, high operating temperature, and high operating frequency. GaN is one of the candidates to replace the existing Si devices which are reaching the theoretical limit of the aspects above. Since the quality of GaN chips is still immature, a GaN HEMT device has a couple of unsolved issues. The current collapse phenomenon and the normally on characteristics will limit the benefit in power switching applications. Many researches have presented papers with suggestions on how to improve these issues but they have not been completely fixed yet. Due to such characteristics, we face some difficulties when we measure a GaN device to acquire Structure Functions to analyze its structural details. Several measurement modes were tested and the results are described in this paper. We found that a new measurement method is appropriate to find the Structure Functions for the devices we tested.