Device physics of TRAPATT oscillators
TL;DR: In this paper, a simplified physical model was used to describe TRAPATT (TRApped Plasma Avalanche Triggered Transit) operation, and a complete high-efficiency device design was generated and the dependence of operation on physical parameters was elucidated.
Abstract: This paper utilizes a simplified physical model to describe TRAPATT (TRApped Plasma Avalanche Triggered Transit) operation. By yielding on computational accuracy, a complete high-efficiency device design is generated and the dependence of operation on physical parameters is elucidated. The extreme complexity of the precise differential equations describing TRAPATT operation has made the calculation of a single diode-circuit configuration a tour de force. However, by observing the important features of such a solution, a simplified approach giving realistic answers has been evolved. A theoretical device design has been evolved. This design provides device width and impurity density as a function of TRAPATT frequency, and indicates a decreasing degree of "reach through" with increasing frequency. In addition, the explicit dependence of width and impurity density on the diode's reverse saturation current has been obtained. The launching of the avalanche zone through the diode, and, in particular, the limitations implicit in the recovery to a swept-out state, are of broad significance in other types of diodes, particularly p-i-n switches and "snap" diodes.
Citations
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01 Aug 1971
TL;DR: A brief review summarizes mechanisms of operation, power output, efficiency, noise, and some important features of design and fabrication of microwave avalanche diodes of various types.
Abstract: Microwave avalanche diodes of various types (IMPATT, TRAPATT, etc.) can generate power sufficient for microwave receivers and some transmitters. This brief review summarizes mechanisms of operation, power output, efficiency, noise, and some important features of design and fabrication.
112 citations
05 May 1969
TL;DR: In this article, the authors describe and analyze the circuits which have been used successfully for TRAPATT oscillator studies and yield a simple model of the oscillator which is useful for circuit design.
Abstract: This paper describes and analyzes the circuits which have been used successfully for TRAPATT oscillator studies. The results lead to a better understanding of the TRAPATT oscillator and yield a simple model of the oscillator which is useful for circuit design. The circuit characteristics of an experimental TRAPATT oscillator are determined from measurements on the circuits and from equivalent circuit model calculations. The following conclusions can be drawn from the analysis. First, the avalanche diode requires sufficient capacitance near the diode to sustain the high-current state required for TRAPATT operation. Secondly, at a distance from the diode corresponding to approximately one half-wavelength at the TRAPATT frequency the transmission line containing the diode should be terminated by a low-pass filter. The function of the filter is to pass the TRAPATT frequency and to provide a shorting plane for the harmonics of that frequency. Finally, on the load side of the filter, tuning for the TRAPATT frequency is required. The model of the circuit described above suggests a simple explanation of the diode-circuit interaction in a TRAPATT oscillator. Simplified waveforms suggested by the model have been used to calculate power out-put, efficiency, dc voltage change, and RF impedance for the oscillator. The results agree within a few percent with those obtained for an experimental oscillator. An important conclusion of the analysis is that the high-efficiency operation of avalanche diodes at frequencies in the UHF range can be explained by the TRAPATT theory, even though the trapped-plasma or low-voltage state may last only 1/20th of the oscillation period.
84 citations
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08 Sep 2005
TL;DR: In this paper, a static and dynamic breakdown of the Avalanche Multiplication and Injection Injection was discussed, along with a static Avalanche Breakdown and a dynamic Breakdown.
Abstract: # Avalanche Multiplication # Static Avalanche Breakdown # Avalanche Injection # Dynamic Breakdown
79 citations
TL;DR: In this paper, a simplified theory of operation of avalanche shaper diodes is presented, based on the results of numerical modeling, and conclusions are drawn on what factors most greatly affect the performance of avalanche-shaper Diodes and one optimized design is provided.
Abstract: Silicon diodes operated in an avalanche breakdown mode can he used to reduce, or sharpen, the rise times of driving pulses. Proper operation of a diode in this manner requires the application of a driving pulse with sufficient time rate of change of voltage dV/dt. The rapidly changing reverse bias produces an electron-hole plasma of sufficient density that the electric field strength in the n region of a p/sup +/-n-n/sup +/ structure is significantly reduced and the plasma is essentially trapped. In effect, the plasma generation causes the device to transition from a high-impedance state to a low-impedance state in a short period of time, and thus acts as a fast closing switch. This paper provides an overview of this mode of operation. A simplified theory of operation is presented. A comparison is made among the results of numerical modeling, the theory of operation of the silicon avalanche shaper (SAS) diode, and the theory of operation of the trapped-plasma avalanche-triggered transit (TRAPATT) mode of operation of a diode. Based on the results of numerical modeling, conclusions are drawn on what factors most greatly affect the performance of avalanche shaper diodes, and one optimized design is provided.
69 citations
TL;DR: In this paper, a new generation of DLDs called deep-level dynistors (DLDs) is described, which are able to form high-current pulses with sub-nanosecond rise time and low residual voltage just after switching.
Abstract: Power kilovolt electric pulses with subnanosecond rise time can be formed by means of semiconductor switches based on the propagation of ionization fronts in Si structures. We describe a new generation of such devices-which are deep-level dynistors (DLDs). The triggering of the ionization front in the DLDs occurs due to the field-enhanced ionization of deep-level electron traps. The DLDs are able to form high-current pulses with subnanosecond rise time and low residual voltage just after switching. We describe two power generators based on the DLDs as examples. In addition, we discuss the possibility of picosecond switching based on tunneling-assisted impact-ionization fronts.
59 citations
Cites background from "Device physics of TRAPATT oscillato..."
...fronts in microwave trapped-plasma avalanche triggered-transit diodes [ 11 ], [12]....
[...]
...a “superfast” velocity becomes possible due to the presence of small concentrations of free carriers that initiate avalanche multiplication in the SCR as soon as the electric field overcomes Eb. The front velocity V is mostly controlled by the strength of the electric field in the high-field region [ 11 ], [12]....
[...]
References
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01 Apr 1967
TL;DR: Silicon avalanche diodes with a pnn+mesa structure were made according to suitably chosen design parameters, and carefully fabricated to meet stringent pedormance specifications, operating under pulse conditions with a duty factor of approximately 10-3, efficiencies as high as 25 percent, and power outputs up to 435 watts at 425 megahertz as discussed by the authors.
Abstract: Silicon avalanche diodes with a pnn+mesa structure were made according to suitably chosen design parameters, and carefully fabricated to meet stringent pedormance specifications. Operating under pulse conditions with a duty factor of approximately 10-3, efficiencies as high as 25 percent, and power outputs up to 435 watts at 425 megahertz, were achieved.
116 citations
01 Sep 1968
TL;DR: In this paper, computer simulation of diode and circuit behavior has provided an explanation for the observed results of the Ge avalanche diodes at frequencies of 2-3 GHz at 2.5 GHz.
Abstract: Pulsed operation of Ge avalanche diodes has produced oscillations with efficiencies exceeding 40 percent at frequencies of 2-3 GHz. Computer simulation of diode and circuit behavior has provided an explanation for the observed results.
66 citations
TL;DR: In this paper, a steady state can be found in which the generation of carriers in the filament by impact ionization is balanced by radial diffusion of carriers, and the total filament current is a decreasing function of the applied voltage.
Abstract: Space-charge effects in avalanching p+-i-n+diodes give rise to a current-controlled bulk negative resistance. It is shown that this negative resistance gives rise to an instability which tends to lead to the formation of current filaments. A steady state can be found in which the generation of carriers in the filament by impact ionization is balanced by radial diffusion of carriers. We present the results of approximate numerical calculations of filament current-density profiles and total filament current as a function of applied voltage. The total filament current is a decreasing function of the applied voltage; thus, the diode exhibits a quasistatic negative external resistance. It is suggested that this negative resistance may be used to interpret observed sub-transit-time oscillations of p+-i-n+structures.
34 citations
01 Sep 1968
TL;DR: In this paper, room-temperature operation of Ge Impatt diodes with efficiencies as high as 43 percent in the 400 to 1000 MHz frequency range has been achieved.
Abstract: CW room-temperature operation of Ge Impatt diodes with efficiencies as high as 43 percent in the 400 to 1000 MHz frequency range has been achieved. In this low-frequency, high-efficiency mode, the dc voltage drop across the diode is observed to decrease significantly.
29 citations
TL;DR: In this article, a new transient mode of avalanche breakdown in p−n junctions is described. And an approximate analysis is given, and compared with numerical calculations, in order to interpret the observed high efficiency microwave oscillations of the trapped plasmas ''TRAPATT'' mode.
Abstract: A new transient mode of avalanche breakdown in p‐n junctions is described. For sufficiently high current, a region of impact ionization of carriers advances as a shock front whose velocity can be several times faster than the carrier‐saturated drift velocity. Since the passing disturbance rapidly fills the depletion region with a dense plasma of holes and electrons, it has been used to interpret the observed high‐efficiency microwave oscillations of the trapped‐plasma ``TRAPATT'' mode. An approximate analysis is given, and compared with numerical calculations.
28 citations