# Computer studies of the effect of electron and hole current multiplication factors on the d.c. and microwave properties of symmetrical Si DDR IMPATT devices

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TL;DR: In this article, the effect of reverse saturation current on the high frequency and low frequency of a silicon double-drift region (DDR) operating in the mm-wave range (W-band) was investigated.

Abstract: Computer studies have been carried out on the effect of electron and hole reverse saturation current on the high frequency (i) negative resistance and reactance profiles, (ii) admittance characteristics, and (iii) device quality factor of a silicon double-drift region (DDR) IMPATT operating in the mm-wave range (W-band). The results indicate that the negative resistance peaks in the electron and hole drift layers decrease with increasing reverse saturation current. The total diode negative resistance also decreases appreciably with the increase of either electron or hole reverse saturation current, ie, with decrease in electron or hole current multiplication factors (M & Mp).It has further been observed that in the lower frequency range of the W-band, the device negative conductance decreases with the increase of reverse saturation current, while in the frequency range from 160–210 GHz, the device negative conductance increases with the enhancement of reverse saturation current.An upward frequency shift b...

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Bell Labs

^{1}TL;DR: In this article, the authors presented theoretical calculations of the large-signal admittance and efficiency achievable in a silicon p-n-v-ns Read IMPATT diode.

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.

1,960 citations

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TL;DR: In this article, the drift velocity of electrons and holes in silicon has been measured in a large range of the electric fields (from 3. 102to 6. 104V/cm) at temperatures up to 430 K. The mean square deviation was in all cases less than 3.8 percent.

Abstract: The drift velocity of electrons and holes in silicon has been measured in a large range of the electric fields (from 3 . 102to 6 . 104V/cm) at temperatures up to 430 K. The experimental data have been fitted with a simple formula for the temperatures of interest. The mean square deviation was in all cases less than 3.8 percent. A more general formula has also been derived which allows to obtain by extrapolation drift velocity data at any temperature and electric field.

528 citations

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Bell Labs

^{1}TL;DR: In this article, the ionization rates of charge carriers in silicon have been measured and fit to the recent theoretical calculations of Baraff; in contrast, none of the existing published data could fit to these theoretical curves.

Abstract: The ionization rates of charge carriers in silicon have been measured and fit to the recent theoretical calculations of Baraff; in contrast, none of the existing published data could be fit to these theoretical curves The study has been made using microplasma-free junctions of demonstrably high, uniform local multiplication A new and considerably simplified approach to the problem of extracting the ionization rates from the multiplication data has been used By employing much more precise control of the electron and hole currents used to initiate the multiplication process, the hole ionization rate at electric fields less than 300 kV/cm is found to be more than an order of magnitude smaller than any previously published measurements Hole and electron ionization rates have been measured in the same junction and consequently in the identical scattering environment The threshold energy is determined to be ${E}_{g}\ensuremath{\le}{E}_{i}\ensuremath{\le}15{E}_{g}$, and the mean free path for scattering of high-energy electrons is $50 \AA{}\ensuremath{\le}{\ensuremath{\lambda}}_{e}\ensuremath{\le}70 \AA{}$ and for energetic holes $30 \AA{}\ensuremath{\le}{\ensuremath{\lambda}}_{h}\ensuremath{\le}45 \AA{}$ Measurement of ionization rates at various temperatures substantiates the assumption that the energy-loss mechanism is the emission of optical phonons In addition, significant differences of the electrical breakdown characteristics of microplasma-free junctions are discussed as well as their preparation

442 citations

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Bell Labs

^{1}TL;DR: In this paper, a general small-signal theory of the avalanche noise in IMPATT diodes is presented, which is applicable to structures of arbitrary doping profile and uses realistic (α
eq \beta in Si) ionization coefficients.

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.

229 citations

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Bell Labs

^{1}TL;DR: The basic principles of IMPATT diodes as microwave devices are reviewed and the current status of these devices concerning power output and efficiency is given in this article, where an approximate, but realistic, diode model is employed.

Abstract: The basic principles of IMPATT diodes as microwave devices are reviewed and the current status of these devices concerning power output and efficiency is given. The main purpose of this paper, however, is to discuss the nonlinear properties of these diodes which are useful in the design of amplifiers, oscillators, and other microwave devices. The main results of this paper are obtained from a digital computer analysis where an approximate, but realistic, diode model is employed. A detailed comparison of complementary silicon diodes as well as GaAs diodes concerning power output and efficiency is given. The effects of doping profile, current density, temperature, and material parameters on the performance of these devices have been investigated and are summarized. Saturation effects which limit the efficiency and power output of these devices are described and optimum efficiencies which can be achieved for various doping profiles are given. A comparison between single-sided and double-drift diodes in both silicon and GaAs is also presented.

63 citations