Enhanced Polarization Charge Utilization in Advanced Embedded-Gate AlGaN/GaN High-Electron-Mobility Transistors to Improve Two-Dimensional Electron Gas Confinement

This work presents a novel AlGaN/GaN high-electron-mobility transistor (HEMT) structure, named the Advanced Embedded-Gate HEMT (AEG-HEMT), designed to enhance the influence and utilization of polarization charges for improving device performance. In GaN-based HEMTs, spontaneous and piezoelectric polarization effects at the AlGaN/GaN interface induce a strong built-in electric field that enables the formation of a high-density two-dimensional electron gas (2DEG). The proposed AEG-HEMT embeds the gate into the AlGaN barrier and introduces an adjacent N-type Silicon-doped AlGaN field plate to optimize the vertical and lateral electric field distributions. Our results show that the embedded gate significantly increases the vertical electric field, thereby enhancing the coupling between the gate bias and polarization charges, which improves 2DEG confinement and carrier density. Additionally, the N-type Si-doped field plate reduces electric field crowding at the gate edge, improving breakdown voltage and current capability. Compared to conventional HEMTs, the AEG-HEMT achieves higher drain current, improved transconductance, and lower recombination rates, validating the advantages of polarization charge enhancement through structural design.