The Tunnel Diode Super-regenerative Amplifier†

An X-band tunnel diode amplifier (TDA) has been studied for SGEMP response. This study has involved analytical modeling and predictions, tunnel diode electrical pulsing to develop damage statistics, and experimental measurements in an 800 kvp flash X-ray environment. In contrast to photocurrent limited TREE response, significant SGEMP replacement currents can flow through the tunnel diode. This response is associated with mechanical design, the use of gold-plated conductors facing aluminum surfaces within a cavity with corresponding photoemission differences and the differences in fore and back emission between the tunnel diode amplifier and the evacuated test chamber walls. The SGEMP current is independent of bias circuit design. The modeling and prediction effort included SGEMP current determination, electrical circuit modeling and computerized transient radiation circuit analysis. The experimental SGEMP tests were performed in vacuum using the BLACK-JACK 3 (BJ3) facility at Maxwell Laboratories, Inc., in San Diego, California. Measurements are reported for the current responses of the tunnel diode and the circulator. Eight tunnel diodes were damaged due to SGEMP and their damage threshold energies were calculated, using tunnel diode characteristics, radiation dose and SGEMP currents. Damage frequency data for the BJ3 tests correlates with separate electrical pulse data and supports the conclusion that the SGEMP response of TDA's is predictable using the model developed in this study.

This paper presents results of numerical simulations of a III-V dual-junction solar cell including tunnel diode and Bragg reflector. The simulations are carried out in a commercially available semiconductor simulation environment. For the computation of the quantum efficiency of the subcells a special procedure using biasillumination and bias-voltage is implemented. The model is validated by a comparison of simulated external quantum efficiency (EQE) and IV curve with experimental data. A very good agreement is achieved. Simulations are used to illustrate the influence of the Bragg reflector and the tunnel diode on the EQE. Additionally, the capabilities of the model for design optimization are exemplified by an adaption of the subcells’ thicknesses.

Owing to the similarity of the junction widths and doping levels in epitaxially formed GaAs lasers and conventional tunnel diodes, the gradual degradation of the latter under use might be expected to be intensified in the case of lasers operating under high duty cycle or CW conditions. It was found that the current-voltage characteristics of both the lasers and tunnel diodes underwent considerable thermal degradation even when no bias was applied, and that the degradation was limited to surface or "junction edge" effects. The degradation of the current-voltage characteristic was correlated with degradation in the light output under forward bias. It was concluded that degradation under forward bias was also a surface effect induced by heating rather than by deterioration of the junction in the bulk, as commonly believed. Methods of controlling the degradations are discussed.

An oscillator with a series connection of tunneling diodes produces significantly higher power than a single diode oscillator. However, a circuit with series-connected tunneling diodes biased simultaneously in the negative differential resistance (NDR) region of the I-V curve is dc unstable. This dc instability makes the series connection oscillator fundamentally different from a single diode oscillator. Associated with the dc instability are the phenomena of minimum oscillation amplitude and frequency. Due to the minimum oscillation amplitude, it is critical to provide the impedance match between the oscillator circuit and the series connection at the desired oscillation amplitude level. An in depth, comprehensive analysis of the dc instability is given here. Based on this analysis, a numerical procedure is developed to accurately predict the minimum oscillation amplitude and frequency. Time domain simulations which give further insight into series-connection oscillator behavior are discussed. The effect of increasing the number of diodes on the oscillator performance is explored as well. Based on numerical and simulation results, oscillators with several tunnel diodes connected in series were designed and tested. Experimental results that confirm the existence of the minimum oscillation amplitude are presented for oscillators with two, three, and four tunnel diodes.

On the theory of hall-effect isolators for tunnel diode amplifiers

Esaki diode-transistor circuits have demonstrated potential switching speeds of less than one milli-microsecond. Such circuits require Esaki diodes with extremely low junction capacitances, and peak currents generally between one and six milliamperes. This paper describes the design and construction of very high speed, low peak current, germanium Esaki switching diodes. A design criteria is presented which demonstrates the various interactions and limitations between (capacitance/peak current), peak current, and series resistance. Limitations imposed by junction geometry are also presented. The design of a particular high speed Esaki diode with a peak current of five milliamperes, and a junction capacitance of three picofarads, is given together with experimental results. Methods for producing germanium Esaki diodes with peak current tolerances of ± 1% and peak-to-valley ratios as high as 25 : 1 are described.

During the studies of coupling effects between the outer ring and inner circle in a concentric structure of double-metal-insulator-semiconductor tunnel diode, we have proposed an asymmetric coupling effect to account for the distinctive difference between two opposite operations. However, further investigation is needed to make our mechanism more robust. In this work, we designed two sets of ring-shaped and concentric MIS tunnel diode lithographic patterns with a fixed inner fringe in the first set and a fixed outer fringe in the second set. From both the experimental and TCAD-simulated results, we have found that the major role in grabbing charges is the outer fringe of a ring-shaped MIS structure and that this outer fringe-dominated characteristic accompanied with the asymmetric coupling effect results in the observable difference in two contrary operation modes where the inner circle and outer ring take turns to play as the control gate.

A semi-empirical model for the tunnel current-voltage characteristics in Al-SiO 2-Si( p) structures

The current voltage characteristic of the Na, K pump is described on the basis of a modified Post-Albers cycle. The voltage dependence of the rate constants is derived from the elementary chargetranslocations associated with the single reaction steps. Charge displacements result from movements of the sodium- or potassium-loaded binding sites, as well as from motions of polar groups in the pump molecule. If part of the transmembrane voltage drops between the alkali-ion binding sites and the aqueous solution, the binding constants become voltage-dependent. Depending on the values of the microscopic parameters, the current-voltage characteristic may assume a variety of different shapes. Saturating behaviour results when one or more voltage-independent reaction steps become rate limiting. Non-monotonic current-voltage curves exhibiting regions of negative pump conductance are predicted when, at least in one of the transitions, charge is moved against the direction of overall charge-translocation. The theoretical predictions are compared with recent experimental studies of voltage-dependent pump currents.

Tunnel diode is a semiconductor device in which quantum mechanical tunnelling leads to a region of negative slope in the forward direction of current-voltage characteristics. Tunnel diode is made from highly doped semiconductor junctions of very small thickness using materials Ge, GaSb and GaAs. The important features—characteristics, parameters and noise—are discussed in this article.

This paper presents a theory for single-stage circulator-coupled negative resistance reflection amplifiers based on proposed realistic circuit models for frequency-dependent band-limited circulators and broadband negative resistance devices such as the tunnel diode. In particular, gain bandwidth limitations are derived which are imposed by both the inherent resonance associated with the nonreciprocal circulator junction and the reactive parasitic associated with the active device. These limitations are generally more restrictive than past results which assumed a "perfect" frequency-independent circulator and took into account only the device parasitic. In addition, a synthesis procedure is presented for realization of an absolutely stable amplifier with a prescribed nth-order Butterworth or Chebyscheff approximation to an ideally flat band-pass power gain characteristic. The approach employed is based upon the theory of reflection coefficient equalization between two reactively constrained resistances representing the pass band circulator and device immittance models. In addition, a band rejection out-of-band stabilizing network is absorbed in the pass band equalizer in accordance with an over-all synthesis procedure. Finally, the theory is verified by the construction and testing of an L-band tunnel diode amplifier having third-order maximally flat power gain centered at 1.46 Gc/s and with half-power bandwidths (430 Mcls and 355 Mc/s at 10 dB and 16dB midband gain) within six percent of those predicted by theory.

Topological insulators (TIs) open up many avenues for designing future electronic devices. Using the Bardeen transfer Hamiltonian method, we calculate the current density of electron tunneling between two slabs of $\mathrm{Bi}$${}_{2}$$\mathrm{Se}$${}_{3}$. We calculate the three-dimensional TI tunnel-diode current-voltage (J-V) characteristics for different doping concentrations, tunnel-barrier heights and thicknesses, and 3D-TI band gaps. The difference in the Fermi levels of the slabs determines the peak and valley voltages. The tunnel-barrier width and height affect the magnitude of the current without affecting the shape of the $J$-$V$ characteristics. The band gap of the 3D TI determines the magnitude of the tunnel current, albeit at a lesser rate than the tunnel-barrier potential; thus the device characteristics are robust under changing TI material. The high peak-to-valley ratio of 3D-TI tunnel diodes, the controllability of the valley-current location, and the simple construction provide advantages over other negative-differential resistance devices.

In this paper an attempt is made to present the work on microwave components/sub-assemblies that is being carried out at Himalayan Radio Propagation Unit, using microwave printed circuit techniques. The various microwave components/sub-assemblies designed and developed for the microwave communication system under development include the power divider, hybrid ring, directional couplers, balanced mixer and tunnel diode amplifier. The microwave printed circuits have the advantages of reduction in size and weight, better reliability and improved electrical performance over the conventional waveguide and coaxial microwave components.

AM to PM conversion in tunnel diode amplifiers

This paper provides an Analog Behavioral Model (ABM) in Pspice of a tunnel diode The Pspice parameters are implemented as separate parameterized blocks constructed from Spice (ABM) controlled sources and extracted through experiment. A tunnel diode based oscillator is also proposed and simulated using circuit analysis software. The behavior of the tunnel diode is simulated and compared to the measured data to show the accuracy of the Pspice model. Close agreement was obtained between the simulation and experimental results.