Modeling the small signal characteristics of an ALD Al2O3 insulated-gate AlN/GaN high electron mobility transistor

In this work the authors show the employment of an atomic layer deposited (ALD) high-K AI₂O₃ gate oxide in an AIN/GaN HEMT that suppresses the unwanted gate current and simultaneously enhances parasitic influence on frequency performance. Small signal modeling of the Al₂O₃/AlN/GaN HEMT has allowed the accurate extraction of this detrimental influence on device RF performance. It was shown that both intrinsic f_t and f_max are notably higher when parasitic elements are removed from S-parameter data, as expected. These results provide a more accurate understanding of the intrinsic functionality of the AIN/GaN HEMT and serve as a guide for further refinements of the device.