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 powerPRFrises from 2.30 to 3.06 MW/cm2, and the maximum conversion efficiencyηrises from 14.7% to 18.5%. In addition, simulation results reveal that the trench lengthLᵣand depthDᵣof the 2-DEG channel significantly influence the output performances of HIMPATT diode, where the frequency characteristic is more sensitive to the trench lengthLᵣand the RF power characteristic is more sensitive to the trench depthDᵣ. 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.