Study of Self-heating Effect of GaN HEMTs with Buffer Traps by Low Frequency S-parameters Measurements and TCAD Simulation

The effect of self-heating of GaN HEMTs on low frequency S-parameters has been studied by using TCAD simulation. The Im(Y22) for low frequency S-parameters measurement is useful to study buffer trap in GaN HEMTs. The self-heating effect affects a peak indicated trap in Im(Y22) depending on measurement frequency. The frequency of peak by trap shifts toward higher as channel temperature increase. Moreover, the self-heating effect generates a peak in Im(Y22) vs. frequency. The frequency of peak generated by self-heating effect only is almost constant as channel temperature increase. Furthermore, this TCAD results show good agreement with the measurement results.