IMPATT diode

About: IMPATT diode is a research topic. Over the lifetime, 1295 publications have been published within this topic receiving 12298 citations.

Large-signal analysis of a silicon Read diode oscillator

Abstract: This paper presents theoretical calculations of the large-signal admittance and efficiency achievable in a silicon p-n-v-ns Read IMPATT diode. A simplified theory is employed to obtain a starting design. This design is then modified to achieve higher efficiency operation as specific device limitations are reached in large-signal (computer) operation. Self-consistent numerical solutions are obtained for equations describing carrier transport, carrier generation, and space-charge balance. The solutions describe the evolution in time of the diode and its associated resonant circuit. Detailed solutions are presented of the hole and electron concentrations, electric field, and terminal current and voltage at various points in time during a cycle of oscillation. Large-signal values of the diode's negative conductance, susceptance, average voltage, and power-generating efficiency are presented as a function of oscillation amplitude for a fixed average current density. For the structure studied, the largest microwave power-generating efficiency (18 percent at 9.6 GHz) has been obtained at a current density of 200 A/cm2, but efficiencies near 10 percent were obtained over a range of current density from 100 to 1000 A/cm2.

A proposed high-frequency, negative-resistance diode

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.

The potential of diamond and SiC electronic devices for microwave and millimeter-wave power applications

Abstract: The potential of SiC and diamond for producing microwave and millimeter-wave electronic devices is reviewed. It is shown that both of these materials possess characteristics that may permit RF electronic devices with performance similar to or greater than what is available from devices fabricated from the commonly used semiconductors, Si, GaAs, and InP. Theoretical calculations of the RF performance potential of several candidate high-frequency device structures are presented: the metal semiconductor field-effect transistor (MESFET), the impact avalanche transit-time (IMPATT) diode, and the bipolar junction transistor (BJT). Diamond MESFETs are capable of producing over 200 W of X-band power as compared to about 8 W for GaAs MESFETs. Devices fabricated from SiC should perform between these limits. Diamond and SiC IMPATT diodes also are capable of producing improved RF power compared to Si, GaAs, and InP devices at microwave frequencies. RF performance degrades with frequency and only marginal improvements are indicated at millimeter-wave frequencies. Bipolar transistors fabricated from wide bandgap material probably offer improved RF performance only at UHF and low microwave frequencies. >

A small-signal theory of avalanche noise in IMPATT diodes

Abstract: A general small-signal theory of the avalanche noise in IMPATT diodes is presented. The theory is applicable to structures of arbitrary doping profile and uses realistic ( \alpha eq \beta in Si) ionization coefficients. The theory accounts in a self-consistent manner for space-charge feedback effects in the avalanche and drift regions. Two single-diffused n-p diodes of identical doping profile, one of germanium and the other of silicon, are analyzed in detail. For description of the noise of the diodes as small-signal amplifiers the noise measure M is used. Values for M of 20 dB are obtained in germanium from effects in the depletion region only, i.e., when parasitic end region resistance is neglected. Inclusion of an assumed parasitic end resistance of one ohm for a diode of area 10-4cm2produces the following noise measure at an input power of 5×104W/cm2, and at optimum frequency: germanium 25 dB, silicon 31 dB. For comparison, a noise figure of 30 dB has been reported [1] for a germanium structure of the same doping profile as used in the calculations. Measurements of silicon diodes of the same doping profile are not available, but typically silicon diodes give 6-8 dB higher noise figures than germanium diodes of comparable doping profile.

Optical control of microwave semiconductor devices

Abstract: The use of optically controlled devices to perform a range of circuit functions is reviewed. The optical control of amplifier performance is discussed. The optical control of two- and three-terminal oscillators and optically pumped mixers is discussed. Among the active devices treated are Gunn and IMPATT oscillators; MESFET and HEMT amplifiers, oscillators, and mixtures; and diode mixers. Future directions for research in this area are discussed. >