Effects of tunnelling current on millimetre-wave IMPATT devices
TL;DR: In this paper, the influence of tunnelling on the RF performance of millimetre-wave (mm-wave) impact ionisation avalanche transit time (IMPATT) diodes was studied by taking into account the parasitic series resistance of the device.
Abstract: In this paper, the influence of tunnelling on the RF performance of millimetre-wave (mm-wave) impact ionisation avalanche transit time (IMPATT) diodes operating in mixed tunnelling and avalanche transit time mode is studied by taking into account the parasitic series resistance of the device. The results show that the parasitic resistance of mm-wave IMPATTs increases and consequently the power delivered by the device decreases due to the consequence of band-to-band tunnelling. The critical background doping concentration and operating frequency are found to be 5.0 × 1023 m−3 and 260 GHz, respectively, above which the influence of tunnelling on the RF performance of the device becomes predominant.
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TL;DR: In this article, a self-consistent quantum drift-diffusion model for multiple quantum well (MQW) impact avalanche transit time (IMPATT) diodes is presented, where the bound states in MQWs have been taken into account by selfconsistent solutions of the coupled classical driftdiffusion (CLDD) equations and time independent Schrodinger equations associated with both the conduction and valence bands.
Abstract: In this paper, the authors have presented a self-consistent quantum drift-diffusion model for multiple quantum well (MQW) impact avalanche transit time (IMPATT) diodes. The bound states in MQWs have been taken into account by self-consistent solutions of the coupled classical drift-diffusion (CLDD) equations and time-independent Schrodinger equations associated with both the conduction and valence bands. The static and high-frequency properties of MQW DDR IMPATTs based on Si$$\sim $$~3C-SiC material system designed to operate near 94-GHz atmospheric window have been studied by means of the above-mentioned self-consistent solutions of coupled CLDD equations and Schrodinger equations followed by a well-established double-iterative field maximum computational technique. A symmetric and two complementary asymmetric doping profiles for the proposed structures have been taken into account for the present study. The RF power outputs of Si$$\sim $$~3C-SiC MQW DDR IMPATTs near 94 GHz obtained from the simulation are compared with the experimentally obtained power outputs of flat DDR IMPATT diodes based on Si, GaAs, and InP at the same frequency band. It is observed that Si$$\sim $$~3C-SiC MQW DDR IMPATTs are capable of delivering significantly higher RF power compared with IMPATTs based on the above-mentioned materials especially when the doping concentrations of 3C-SiC layers are kept higher than those of the Si layers.
22 citations
TL;DR: In this paper, a large-signal simulation technique has been developed by incorporating the quantum potentials in the current density equations for the analysis of double-drift region IMPATT devices based on different semiconductors.
Abstract: The authors have developed a quantum corrected drift-diffusion model for impact avalanche transit time (IMPATT) devices by coupling the density gradient model with the classical drift-diffusion model. A large-signal simulation technique has been developed by incorporating the quantum potentials in the current density equations for the analysis of double-drift region IMPATT devices based on different semiconductors such as Wurtzite---GaN, InP, type-IIb diamond (C), 4H---SiC and Si deigned to operate at different millimeter-wave (mm-wave) and terahertz (THz) frequencies. It is observed that, the RF power output and DC to RF conversion efficiency of the devices operating at higher mm-wave ($$>$$>140 GHz) and THz frequencies reduce due to the incorporation of quantum corrections in the model; but the effect of quantum corrections are negligible for the devices operating at lower mm-wave frequencies ($$\le $$≤140 GHz).
21 citations
TL;DR: In this article, a quantum drift-diffusion model for impact avalanche transit time (IMPATT) devices has been developed by incorporating appropriate quantum mechanical corrections based on density-gradient theory which macroscopically takes into account important quantum mechanical effects such as quantum confinement, quantum tunneling, etc.
Abstract: Quantum correction is necessary on the classical drift-diffusion (CLDD) model to predict the accurate behavior of high frequency performance of ATT devices at frequencies greater than 200 GHz when the active layer of the device shrinks in the range of 150---350 nm. In the present work, a quantum drift-diffusion model for impact avalanche transit time (IMPATT) devices has been developed by incorporating appropriate quantum mechanical corrections based on density-gradient theory which macroscopically takes into account important quantum mechanical effects such as quantum confinement, quantum tunneling, etc. into the CLDD model. Quantum potentials (synonymous as Bohm potentials) have been incorporated in the current density equations as necessary quantum mechanical corrections for the analysis of millimeter-wave (mm-wave) and Terahertz (THz) IMPATT devices. It is observed that the large-signal (L-S) performance of the device is degraded due to the incorporation of quantum corrections into the model when the frequency of operation increases above 200 GHz; while the effect of quantum corrections are negligible for the devices operating at lower mm-wave frequencies.
17 citations
TL;DR: In this article, the authors explored the potentiality of semiconducting type-IIb diamond as the base material of double-drift region (DDR) impact avalanche transit time (IMPATT) devices operating at both millimetre-wave (mm-wave) and terahertz (THz) frequencies.
Abstract: An attempt is made in this paper to explore the potentiality of semiconducting type-IIb diamond as the base material of double-drift region (DDR) impact avalanche transit time (IMPATT) devices operating at both millimetre-wave (mm-wave) and terahertz (THz) frequencies. A rigorous large-signal (L-S) simulation based on the non-sinusoidal voltage excitation (NSVE) model developed earlier by the authors is used in this study. At first, a simulation study based on avalanche response time reveals that the upper cut-off frequency for DDR diamond IMPATTs is 1.5 THz, while the same for conventional DDR Si IMPATTs is much smaller, i.e. 0.5 THz. The L-S simulation results show that the DDR diamond IMPATT device delivers a peak RF power of 7.79 W with an 18.17% conversion efficiency at 94 GHz; while at 1.5 THz, the peak power output and conversion efficiency decrease to 6.19 mW and 8.17% respectively, taking 50% voltage modulation. A comparative study of DDR IMPATTs based on diamond and Si shows that the former excels over the later as regards high frequency and high power performance at both mm-wave and THz frequency bands. The effect of band to band tunneling on the L-S properties of DDR diamond and Si IMPATTs has also been studied at different mm-wave and THz frequencies.
14 citations
TL;DR: In this paper, the effect of steady magnetic field on the RF performance of millimeter-wave (mm-wave) double-drift region impact avalanche transit time device was investigated.
Abstract: In this paper, a two-dimensional (2-D) large-signal model has been presented to study the effect of steady magnetic field on the RF performance of millimeter-wave (mm-wave) double-drift region impact avalanche transit time device. Magnetic field sensitivities of various static and large-signal parameters of the device designed to operate at W-band have been calculated and discussed in detail. Results show that the frequency tuning of the source of around 3.64 GHz is achievable with maximum sensitivity of about $$-$$-1.59 GHz $$\hbox {T}^{-1}$$T-1 for the application of transverse magnetic field varying from 4.0 to 5.0 T. The nature of both frequency and power tuning of the device due to application of transverse magnetic field is in good agreement with the experimental results carried out earlier.
13 citations
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14,205 citations
"Effects of tunnelling current on mi..." refers result in this paper
...This frequency corresponds to the background doping level of nearly 5.0 × 1023 m−3 which is in close agreement with the reported results (Culshaw & Giblin, 1974; Haddad, Greiling, & Schroeder, 1970; Sze, 1981)....
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...The first fundamental device equation, i.e. Poisson’s equation (Sze, 1981), taking into account the mobile space charge (Gibbons, 1973; Sridharan & Roy, 1978, 1980) in the space charge region of the device is given by: d xð Þ dx ¼ q εs ND xð Þ NA xð Þ þ p xð Þ n xð Þð Þ; (1) where ξ(x) is the…...
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TL;DR: In this paper, the theory of ''direct'' and ''phonon assisted'' tunneling is reviewed and theoretical I-V characteristics are calculated using the constant field model and generalizations to nonconstant field and more complicated band structure models are discussed briefly.
Abstract: The theory of ``direct'' and ``phonon‐assisted'' tunneling is reviewed. Theoretical I–V characteristics are calculated using the constant field model. Generalizations to nonconstant field and more complicated band structure models are discussed briefly.
914 citations
"Effects of tunnelling current on mi..." refers methods in this paper
...The electron tunnelling generation rate was obtained from the thorough quantum mechanical analysis reported earlier (Elta, 1978; Kane, 1961), and it is given by:...
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...…Þ Jn xð Þ ¼ 2 GA xð Þ þ γ xð Þð Þ þ GTn xð Þ þ GTp xð Þ: (7) The electron tunnelling generation rate was obtained from the thorough quantum mechanical analysis reported earlier (Elta, 1978; Kane, 1961), and it is given by: GTn xð Þ ¼ aT 2 xð Þ exp bT xð Þ : (8) The coefficients aT and bT in…...
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TL;DR: In this paper, a semiconductor diode designed to operate as an oscillator when mounted in a suitable microwave cavity is described and analyzed, and it appears possible to obtain over 20 watts of ac power in continuous operation at 5 kmc.
Abstract: This paper describes and analyzes a proposed semiconductor diode designed to operate as an oscillator when mounted in a suitable microwave cavity. The frequency would be in the range extending from 1 to 50 kmc. The negative Q may be as low as 10 and the efficiency as high as 30 per cent. The diode is biased in reverse so as to establish a depletion, or space-charge, layer of fixed width in a relatively high resistance region, bounded by very low resistance end regions. The electric field has a maximum at one edge of the space-charge region, where hole-electron pairs are generated by internal secondary emission, or avalanche. The holes (or electrons) travel across the space-charge layer with constant velocity, thus producing a current through the diode. Because of the build-up time of the avalanche, and the transit time of the holes across the depletion layer, the alternating current is delayed by approximately one-half cycle relative to the ac voltage. Thus, power is delivered to the ac signal. When the diode is mounted in an inductive microwave cavity tuned to the capacity of the diode, an oscillation will build up. It appears possible to obtain over 20 watts of ac power in continuous operation at 5 kmc.
521 citations
"Effects of tunnelling current on mi..." refers background in this paper
...…Journal of Electronics, 2015 Vol. 102, No. 9, 1429–1456, http://dx.doi.org/10.1080/00207217.2014.982211 © 2014 Taylor & Francis In the year 1958, WT Read considered the tunnelling generated current to analyse the IMPATT operation in his renowned paper (Read, 1958)....
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...In the year 1958, WT Read considered the tunnelling generated current to analyse the IMPATT operation in his renowned paper (Read, 1958)....
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TL;DR: In this article, the behavior of oscillators with multiple-resonant circuits is discussed, and the condition for free-running stable oscillations, injection locking phenomena, the stable locking range, and a condition for parasitic oscillations are discussed.
Abstract: This paper discusses the behavior of oscillators with multiple-resonant circuits. It discusses the condition for free-running stable oscillations, the injection locking phenomena, the stable locking range, the noise of free-running and injection-locked oscillators, and a condition for parasitic oscillations in detail, and presents a graphical interpretation of this study for clarity. Finally, this paper shows how broadbanding of oscillators can be achieved with a double-resonant circuit. This provides a systematic guide for the design of broadband frequency deviators and broadband injection-locked oscillators for numerous applications.
485 citations
"Effects of tunnelling current on mi..." refers background in this paper
...…power transfer theorem, the real part of the device impedance must be matched to the real part of the load impedance by using a matching circuit with minimum loss at the resonant frequency at which the magnitude of the reactance of the device is equal to that of the circuit (Kurokawa, 1969)....
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...…RF circuit may be expressed as: ZRF ¼ jωL 1g 1 g þ jωL ¼ ω 2L2g þ jωL 1þ ω2L2g2 : (33) In a practical oscillator circuit, the Kurokawa condition of steady-state oscillation (Kurokawa, 1969) is given by: ZDP þ ZRF ¼ 0; thus, both the real and imaginary parts of that must be separately equal to zero....
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...But in case of steady-state free running oscillator, the Kurokawa condition ((Kurokawa, 1969) (i.e. Real ZDP þ ZRFð Þ ¼ 0) must hold....
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...The oscillation goes on to build up for a number of cycles until the magnitude of the negative conductance of the device decays to the value of positive conductance of the RF circuit and the oscillation finally becomes stable (Kurokawa, 1969)....
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