Simulation Study of Lateral Schottky Barrier IMPATT Diode Based on AlGaN/GaN 2-DEG for Terahertz Applications

In this article, a novel lateral Schottky barrier high-low impact-ionization-avalanche-transit-time (IMPATT) diode, i.e., the high-electron mobility transistor (HEMT)-like IMPATT (HIMPATT) diode, is proposed based on the AlGaN/GaN 2-D electron gas (2-DEG). Numerical simulation demonstrated that the HIMPATT diode shows better characteristics than the conventional vertical IMPATT diode because of a superior property of the AlGaN/GaN 2-DEG. Comparing with the vertical IMPATT diode, the optimum frequency of HIMPATT diode rises from 260 to 380 GHz, the maximum RF output power $P_{RF}$ rises from 2.30 to 3.06 MW/cm(2), and the maximum conversion efficiency eta rises from 14.7% to 18.5%. In addition, simulation results reveal that the trench length $L_{r}$ and depth $D_{r}$ of the 2-DEG channel significantly influence the output performances of HIMPATT diode, where the frequency characteristic is more sensitive to the trench length $L_{r}$ and the RF power characteristic is more sensitive to the trench depth $D_{r}$ . By designing the pattern shape of the trench area, a monolithic integrated HIMPATT diode oscillator array can be implemented on one chip to generate a wider frequency band with great RF performances than the vertical IMPATT diode. It provides more variable designing options for the applications of the HIMPATT diode in the terahertz regime.