Generalised small signal analysis of a DAR (Double Avalanche Region) Impatt diode
TL;DR: In this paper, a generalised small signal analysis of a DAR Impatt diode has been carried out using recent values of ionisation rates and saturated drift velocities of electrons and holes for Si and GaAs taking both drift and diffusion of charge carriers into account.
Abstract: A generalised small signal analysis of a DAR Impatt diode has been carried out using recent values of ionisation rates and saturated drift velocities of electrons and holes for Si and GaAs taking both drift and diffusion of charge carriers into account. Results show similar discrete negative conductance frequency bands separated by positive conductance frequency bands for asymmetrical structure as in the ideal case[1] establishing that the harmonically related frequencies can be avoid in Si DAR Impatt diode. However, unlike the ideal case, here the symmetrical DAR Impatt also exhibits finite negative conductance. GaAs DAR Impatt shows similar variations of negative conductance as in Si at high frequencies (in the mm wave range) but at the low frequency side (< 1 GHz) it gives uniform negative conductance unlike Si where the negative conductance comes only at higher frequencies. In our calculations we have considered thin depletion layers (0.8, 1 μm and 2 μm) to show the usefulness of the device in the mm wave range. Further, the DAR Impatt will be able to withstand higher biasing current density without thermal runaway due to space charge cancellation and thus will deliver more power than the conventional Impatts.
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TL;DR: In this article, the dc field and current density profiles of a Si n+-p-v-n-p+double avalanche region (DAR) Impatt have been carried out.
Abstract: A computer study on the dc field and current-density profiles of a Si n+-p-v-n-p+double avalanche region (DAR) Impatt has been carried out. With increasing current density the uniform electric field in the central drift region remains almost unaffected due to cancellation of mobile space charge, in case of symmetrically doped structure. Also the avalanche and drift-zone widths and the RF conversion efficiency remain almost unaltered. For asymmetric doping there is a small space-charge effect.
52 citations
TL;DR: In this paper, a large-signal analysis of double-avalanche region (DAR) IMPATT diodes has been presented, and the output power, admittance and efficiency of the device have been derived and their variations with different parameters studied.
Abstract: A large-signal analysis of double-avalanche-region (DAR) IMPATT diodes has been presented. Analytical expressions for the output power, admittance and efficiency of the device have been derived and their variations with different parameters studied. Results show that DAR IMPATT will be useful as a fixed-frequency millimetre-wave oscillator free from harmonics.
6 citations
16 Feb 2004
TL;DR: The numerical model of the diode is developed, which permits analysis of the physical processes in the DAR structure and serves as a first step to a more profound analysis and structure optimization of DAR diodes.
Abstract: The new n/sup +/pvnp/sup +/ avalanche diode structure was proposed some years ago to improve frequency characteristics. This type of diode was named the double avalanche region (DAR) IMPATT diode. This structure includes two avalanche regions inside the diode. The charge carriers multiply in the avalanche region and than drift along the drift zone, v, with constant speed. These carriers multiply once again in the other avalanche zone. The phase delay, produced by the two avalanche zones and the drift zone, is sufficient for negative resistance to be obtained for a wide frequency range. The characteristics of the DAR IMPATT diode can be analyzed on the basis of the numerical precise model. We develop the numerical model of the diode, which permits analysis of the physical processes in the DAR structure. The admittance characteristics of the diode were analyzed in a very wide frequency region. The admittance and generating power dependencies from the amplitude of the first harmonic voltage were analyzed too. The obtained results serve as a first step to a more profound analysis and structure optimization of DAR diodes.
4 citations
TL;DR: In this paper, a double iteration technique is applied to obtain the field and current density profiles of an ionimplanted double avalanche region (DAR) Impatt diode suitable for operation around 94 GHz under steady state condition.
Abstract: A double iteration technique is applied to obtain the field and current density profiles of an ionimplanted double avalanche region (DAR) Impatt diode suitable for operation around 94 GHz under steady state condition. Computations are carried out for Si, InP- and GaAs DAR Impatt. It is found that using ion, implanted structures it will be possible to improve the efficiency of the DAR Impatt considerably at millimeter wave frequencies.
Eine Doppeliterationstechnik wird benutzt, um die Feld- und Stromdichteprofile einer ionenimplantierten Doppel-Lawinenbereichs(DAR)-Impatt-Diode fur Arbeitsfrequenzen um 94 GHz unter stationaren Bedingungen zu erhalten. Berechnungen werden fur Si-, InP- und GaAs- DAR-Impatt-Dioden durchgefuhrt. Es wird gefunden, das es bei Benutzung von implantierten Strukturen moglich ist, den Wirkungsgrad der DAR-Impatt bei Millimeterwellenfrequenzen betrachtlich zu verbessern.
2 citations
TL;DR: The obtained results contradict to the before performed analysis on basis of the approximate models and show that only diode with a sufficiently short drift region can produce active power in some frequency bands.
Abstract: The analysis of the n + p v np + avalanche diode structure has been realized on the basis of the nonlinear model. This type of the diode that was named as double avalanche region (DAR) IMPATT diode includes two avalanche regions inside the diode. The phase delay which was produced by means of the two avalanche regions and the drift region v is sufficient to obtain the negative resistance for the wide frequency band. The numerical model that is used for the analysis of the various diode structures includes all principal features of the physical phenomena inside the semiconductor structure. The admittance characteristics of the DAR diode were analyzed in very wide frequency band. The obtained results contradict to the before performed analysis on basis of the approximate models and show that only diode with a sufficiently short drift region can produce active power in some frequency bands.
2 citations
References
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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.
591 citations
TL;DR: In this article, the ionization rates for electrons and holes were extracted from photomultiplication measurements on silicon p+n mesa diodes for electric fields of 2·0 × 105−7·7 × 105 V/cm at temperatures of 22, 50, 100 and 150°C.
Abstract: Ionization rates for electrons and holes are extracted from photomultiplication measurements on silicon p+n mesa diodes for electric fields of 2·0 × 105−7·7 × 105 V/cm at temperatures of 22, 50, 100 and 150°C. These results are particularly pertinent to the analysis of high-frequency (∼ 100 GHz) silicon IMPATT diodes. The rates obtained here are in reasonable agreement with previously published data of van Overstraeten and DeMan, although slightly larger in magnitude. Calculated curves of breakdown voltage vs background doping level are presented using the room temperature ionization rates. Also a comparison is made to previously reported rates. The new rates provide a closer agreement between predicted and measured breakdown voltages for breakdown voltages less than 70 V.
433 citations
TL;DR: In this article, the negative-resistance avalanche diode has been examined in detail for the small-signal case and the space-charge wave approach has been used in the analysis leading directly to a simple equivalent circuit.
Abstract: Read's theory of the negative-resistance avalanche diode has been examined in detail for the small-signal case. The space-charge wave approach has been used in the analysis leading directly to a simple equivalent circuit and a general expression for the small-signal impedance which includes the significant design and operating parameters. The theory indicates that strong tuning effects will occur through variation of the dc avalanche current. This has been verified experimentally.
218 citations
TL;DR: In this paper, the longitudinal diffusion coefficient of electrons in silicon at 300 K for fields from Ohmic up to 50 kV/cm was measured by means of Monte Carlo calculations with a theoretical model which includes the many-valley (ellipsoidal and nonparabolic) structure of the band, acoustic intravalley, and several f and g intervalley scattering mechanisms.
Abstract: With the time‐of‐flight technique we have measured the longitudinal diffusion coefficient of electrons in silicon at 300 K for fields from Ohmic up to 50 kV/cm. The results have been interpreted by means of Monte Carlo calculations with a theoretical model which includes the many‐valley (ellipsoidal and nonparabolic) structure of the band, acoustic intravalley, and several f and g intervalley scattering mechanisms.
79 citations
TL;DR: In this paper, the ionization rates for electrons and holes are expressed as α=5.6×106 exp(−2.41×106/E) and β=1.5×106
Abstract: Ionization rates in GaAs are determined from the measurement of photocarrier multiplication. Pure electron and hole initiations are achieved by using the novel crater mesa structure and appropriate optical‐injection wavelengths. The ionization rates for holes are greater than that for electrons except at highest fields. This agrees with the studies of Stillman et al., except for the individual values. The ionization rates for electrons and holes are expressed as α=5.6×106 exp(−2.41×106/E) and β=1.5×106 exp(−1.57×106/E), respectively.
64 citations