Plasma-Wave Enhanced THz-Performance of a Nanometer Side-Gated Transistor.

By using a two-dimensional-three-dimensional (2D-3D) combined ensemble Monte Carlo (EMC) model, the performance of a nanometer side-gated transistor is studied at terahertz (THz) region. The transistor is based on a GaN/AlGaN heterosturcture at whose hetero-interface a two-dimensional electron gas (2DEG) is formed. And the side-gate of the transistor is intentionally designed as an insulating trench with a 2DEG area in the center. Simulation results reveal that at low working frequency the performances of the transistor are almost frequency independent. However when the working frequency reaches THz region, obvious enhancements of the performances have been observed. The enhancements are accompanied by two peaks respectively at the frequency of about 4 THz and 6 THz. As such, the frequency-dependent performances become frequency nonmonotonic. Further analysis shows that the performance enhancements can be attributed to the excitations of 2D plasma waves in the side-gate which including a 2DEG area in its center.