A Novel HEMT Structure with N++ Layer for free Current Collapse verified by TCAD

This study presents the design and simulation of a novel High Electron Mobility Transistor (HEMT) structure aimed at addressing the issue of current collapse, a major challenge in high-power and high-frequency applications. The new design incorporates a heavily doped N++ layer to restore the two-dimensional electron gas (2DEG) without requiring the etching of the p-GaN layer, thereby minimizing surface states. Simulations show that the novel structure achieves a threshold voltage of 0.9 V and exhibits almost no current collapse, as compared to traditional HEMTs. While the output current is slightly lower due to partial depletion of the 2DEG by the p-GaN layer, the device shows significant improvements in stability and current collapse mitigation. These findings provide new insights for optimizing HEMT performance in high-frequency electronics.