Device physics and failure mechanisms of deep submicron gate GaN HEMTs for microwave and millimeter-wave applications

This thesis presents the findings of a comprehensive characterization study on GaN-based, gate-scaled HEMTs (with Lg < 0.15 µm) for RF applications. The investigation considers performance, stability, and reliability aspects. Specifically, static and dynamic measurements were conducted for the devices under test to assess the influence of short-channel effects and deep-level traps on their characteristics. This involved double-pulse measurements both in OFF and semi-ON state stress and transient measurements. The observed results are compared with those reported in the literature to determine the nature and location of traps responsible for performance variations. In the end stress test were performed to investigate the reliability of the devices. This research contributes to a deeper understanding of the underlying mechanisms and provides valuable insights for the optimization of future GaN-based device designs.