Analvsis Of The Terahertz AlGaN/GaN Resonant Tunneling Diode

Resonant tunneling diodes（RTDs）which can produce terahertz waves because itsability of working in high frequency, have been focused greatly. Furthermore, RTDsbased on GaAs and InP are largely used, and recently it is reported that GaInAs/AlAsRTD, at room temperature, oscillates fundamentally at1.08THz with the output powerof5.5μW, the highest result in experiment. With the demand of communication forhigher power, RTDs based on GaN are largely studied because it gives out higher power.But polarization and defects between AlGaN/GaN heterostructure, affect itsperformance heavily, until now, all GaN based RTDs degenerate in negative differentialresistance(NDR) characteristic with the measurement increase, so stable THz waves cannot be produced. In this paper, considering the interface defects, AlGaN/GaN RTD arestudied, with its SPICE circuit model, AC characteristics are firstly got. The majorachievements are listed below:1) Problems, current and circuit models of GaN RTDs are concluded, compared GaAsRTDs`μW level, GaN RTDs`output power reaches mW.2) By the changes of barrier, well, Spacer, composition of Al, and dopingconcentration in emitter, the DC Characteristics of GaN RTDs are studied.3) By the study of defects in the AlGaN/GaN quantum well, under a density ofinterface charges and dislocations, GaN RTDs`NDR stops degenerating NDR anddegenerating. This can guide the production of RTDs.4) Considering the parasitic parameters, RTDs`model is built, further, an NDRoscillator is formed, and its RF power and efficiency are firstly got. Finally the Sparameter is got, for further studying.In brief, GaN RTDs are studied comprehensively, until the density of dislocationsbellows106cm-2, can we get a stable NDR. With the NDR oscillator, AlGaN/GaN RTDgives out about22mW RF power, with the DC-RF efficiency of about8%.