High-performance, graded AlGaAs injector, GaAs Gunn diodes at 94 GHz

Couch, N. R.; Spooner, H.; Beton, Peter H.; Kelly, Michael J.; Lee, M.E.; Rees, Philippa; Kerr, T. M.

doi:10.1109/55.29655

Cited by 50 publications

(16 citation statements)

References 10 publications

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“…These simulations were performed with the terminal impedance set to 50Ω with the sole intention of establishing the limits of transit region length capable of supporting a steady-state (non-decaying) oscillation. Generally speaking, this free-running frequency is reduced when the device is embedded in a practical resonant circuit: a full discussion of this concept can be found in 13 . The simulated oscillation frequencies reported here are therefore not expected to precisely match those measured (which are defined by oscillator design), but to be slightly higher.…”

Section: Resultsmentioning

confidence: 99%

“…The plot is taken from 13 and was produced using Monte Carlo simulations of the free running frequency of GaAs Gunn devices with and without hot-electron injection (it is noted that the power curve is based on measured values and that the simulations did not include consideration of an oscillator circuit). This shows that the free-running frequency of oscillation is reduced as the external field is increased, meaning that the oscillation frequency of the simulated time-domain response is typically expected to be higher than that measured from an oscillator circuit.…”

Section: Time-domain and Transient Response Simulationmentioning

confidence: 99%

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Time-domain analysis of sub-micron transit region GaAs Gunn diodes for use in terahertz frequency multiplication chains

et al. 2010

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Simulated RF time-domain characteristics for advanced Gunn diodes with hot electron injection and sub-micron transit region lengths for use at frequencies over 100GHz are reported. The physical models used have been developed in SILVACO and are compared to measured results. The devices measured were originally fabricated to investigate the feasibility of GaAs Gunn diode oscillators capable of operating at D-band frequencies and ultimately intended for use in high power (multi-mW) Terahertz sources (~0.6THz) when used in conjunction with novel Schottky diode frequency multiplier technology. The device models created using SILVACO are described and the DC and time-domain results presented. The simulations were used to determine the shortest transit region length capable of producing sustained oscillation. The operation of resonant disk second harmonic Gunn diode oscillators is also discussed and accurate electromagnetic models created using Ansoft High Frequency Structure Simulator presented. Novel methods for combining small-signal frequency-domain electromagnetic simulations with time-domain device simulations in order to account for the significant interactions between the diode and oscillator circuit are described.

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Section: Resultsmentioning

confidence: 99%

Section: Time-domain and Transient Response Simulationmentioning

confidence: 99%

Time-domain analysis of sub-micron transit region GaAs Gunn diodes for use in terahertz frequency multiplication chains

et al. 2010

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“…1 (for more detail see Refs. [9] and [10]). Each device consists of a graded Al x Ga 1-x As barrier region, grown to have nominal thickness D ≈ 50 nm, with composition x varying from 0 to 0.3; this layer is bounded by two GaAs layers, as shown in Fig.…”

Section: Introductionmentioning

confidence: 94%

Field and thermionic‐field transport in GaAs/AlGaAs/GaAs heterojunction barriers

Morgan

Porch

Krishna

2007

Physica Status Solidi (b)

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This paper considers the transport of conduction band electrons as a result of tunneling through a triangular potential barrier fabricated within a GaAs/Al x Ga 1-x As/GaAs heterojunction. The triangular barrier was formed by the composition grading of the Al x Ga 1-x As region from x = 0 to x = 0.3, which forms part of a cathode emitter in a commercial Gunn diode. The experimental data for the current -voltage characteristics obtained for a range of temperatures from 77 to 273 K were used to test a simplified thermionic-field model. Good agreement has been obtained between theory and experiment, thus confirming the usefulness of this simple model for device evaluation. The comparison of the data over the experimental temperature range shows that the thermionic-field emission observed at 273 K gives way to field emission at 77 K. This is a result of the removal of the more energetic electrons in the conduction band at lower temperatures.

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“…In heterostructural GaN Gunn diode, aluminum gallium nitride (AlGaN) barrier layer is proposed as the HEI layer that forms a slowly increased potential from emitter, i.e., cathode of Gunn diode and an abrupt drop-back potential to the transit region in order to effectively inject lots of high energy electrons into the transit region. 6 Besides it triggers the transition of high energy electrons between the central valley and the upper valley so as to form Gunn domains, this kind of HEI layer simultaneously serves as an interlayer to improve the crystal quality of transit region, in terms of the epitaxial growth of Gunn diode, which is probably an efficient and convenient method because conventional epitaxial growth approaches, such as the epitaxial-lateral-overgrowth (ELOG) and the regrowth, are cumbersome and costly through ex situ processing steps to improve the crystal quality in structures. 7,8 In addition, the aforementioned mechanism could also be applied in the high frequency GaN heterostructural devices, such as AlGaN/GaN high electron mobility transistors (HEMTs) with the dual-channel and the back-barrier structures, AlGaN/GaN heterostructure bipolar transistors (HBTs), AlGaN/GaN/AlGaN dual-barrier resonant tunneling diodes (RTDs), etc., where the AlGaN barrier layer can be used to block part of dislocations from penetrating into the GaN layer, subsequently improve the crystal quality and reduce the surface roughness of GaN active region so as to improve the performance of device.…”

Section: Introductionmentioning

confidence: 97%

Dislocation blocking by AlGaN hot electron injecting layer in the epitaxial growth of GaN terahertz Gunn diode

Yang

Zhang

et al. 2013

Journal of Applied Physics

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This paper reports an efficient method to improve the crystal quality of GaN Gunn diode with AlGaN hot electron injecting layer (HEI). An evident reduction of screw dislocation and edge dislocation densities is achieved by the strain management and the enhanced lateral growth in high temperature grown AlGaN HEI layer. Compared with the top hot electron injecting layer (THEI) structure, the bottom hot electron injecting layer (BHEI) structure enhances the crystal quality of transit region due to the growth sequence modulation of HEI layer. A high Hall mobility of 2934 cm2/Vs at 77 K, a nearly flat downtrend of Hall mobility at the temperature ranging from 300 to 573 K, a low intensity of ratio of yellow luminescence band to band edge emission, a narrow band edge emission line-width, and a smooth surface morphology are observed for the BHEI structural epitaxy of Gunn diode, which indicates that AlGaN BHEI structure is a promising candidate for fabrication of GaN Gunn diodes in terahertz regime.

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High-performance, graded AlGaAs injector, GaAs Gunn diodes at 94 GHz

Cited by 50 publications

References 10 publications

Time-domain analysis of sub-micron transit region GaAs Gunn diodes for use in terahertz frequency multiplication chains

Time-domain analysis of sub-micron transit region GaAs Gunn diodes for use in terahertz frequency multiplication chains

Field and thermionic‐field transport in GaAs/AlGaAs/GaAs heterojunction barriers

Dislocation blocking by AlGaN hot electron injecting layer in the epitaxial growth of GaN terahertz Gunn diode

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