Silicon Double-drift IMPATT Diodes Research Articles

A Study on the Effect of Electron and Hole Saturation Currents on the Negative Resistance Profiles, Negative Conductance and the Frequency of Operation of Millimeter Wave (W-Band) Double-Drift Silicon IMPATT Diodes

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...

Physical understanding and optimum design of high-power millimeter-wave pulsed IMPATT diodes

A physical understanding of the specific mode of operation of high-power millimeter-wave pulsed IMPATT diodes is derived from a self-consistent numerical model. It is shown theoretically that there exists a uniformly avalanching p-i-n-like mode in high-current-density, pulsed silicon double-drift IMPATT diodes, as has been previously suggested. An optimum symmetrical flat doping-profile double-drift structure for 100-GHz operation is presented. It could deliver more than 40 W of available peak power with a 10% conversion efficiency accounting for circuit losses, at a safe junction temperature rise. The theoretical results allow an optimum design of the 94-GHz IMPATT structure for peak output power in excess of 50 W under low duty cycle.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

High-power operation mode of pulsed IMPATT diodes

Pulsed silicon double-drift IMPATT diodes that yield 42 W at 96 GHz are discussed. This is about twice the value reported previously. Owing to the considerable input powers ( approximately=500 W), these diodes are mounted on diamond heat sinks. Because of the strong carrier injection, the field distribution in the diode is similar to that in a p-i-n diode. An attempt is made to explain the results using T. Misawa's (1966) p-i-n type theory. The large-signal; avalanche resonant frequency is close to the operation frequency. Conventional Read-type theory fails to explain these results because of the current densities employed in the experiments. >

Flat doping profile double-drift silicon IMPATT for reliable CW high-power high-efficiency generation in the 94-GHz window

The main results of a theoretical and experimental study of the optimization of flat doping profile double-drift silicon IMPATT diodes for the realization of reliable CW high-power high-efficiency solid-state oscillators operating in the 94 GHz atmospheric propagation window are presented. This study has been carried out by means of an IMPATT oscillator model which takes into account the thermal limitation, bias effect, and diode impedance matching. It relies on an accurate p-n junction device drift-diffusion model that includes the heavily doped regions of the collectors. This model has been used to quantify the influence of the various parameters determining the oscillator RF output performance. An explanation of the interesting noise performance of these millimeter-wave IMPATT diodes is proposed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Effect of Impurity Charge Bumps on the DC and Microwave Properties of High Efficiency Silicon Double Drift Impatt Diodes

The effect of location, width and doping concentration of impurity charge bumps on the dc and microwave properties of various high efficiency double drift structures of Si Impatt diodes has been investigated for V-band (≃ 60 GHz) operation. The study covers symmetrical Hi-Lo and Lo-Hi-Lo DDR structures as well as asymmetrical structures having Hi-Lo profile on one side of the junction and Lo-Hi-Lo profile on the other side. The Lo-Hi-Lo profile pushes the avalanche centre towards the junction and thereby causes a localization of the avalanche zone, whereas, Hi-Lo profile increases maximum field at the junction which in turn produces higher drift voltage drop. The properties of the optimized DDR structures have been discussed with the help of dc field and current profiles and small signal G-B plots. It is found that both symmetrical Lo-Hi-Lo and asymmetrical Hi-Lo/Lo-Hi-Lo DDR structures would provide high efficiency in the range 18–21% and larger small-signal negative conductance compared to flat DDR stru...

A carrier temperature model simulation of a double-drift IMPATT diode

A computer simulation of double-drift silicon IMPATT diodes is presented. The model is essentially the conventional drift-diffusion model with two significant improvements; the ionization coefficients are assumed to be functions of carrier temperature rather than local electric field, and a description of the effects of the carriers' thermal conductivity is included [1]. Our model includes all known hot electron effects except velocity overshoot (hot electron drift, diffusion, relaxation, and heat conduction), and is exact within the framework of an electron temperature model.

Large-signal analysis of Lo-Hi-Lo double-drift silicon IMPATT diodes at 50 GHz

Large-signal analysis of a lo-hi-lo double-drift silicon IMPATT diode at 50 GHz shows that the device is capable of output power of 1.1 W and efficiency of 20 percent for a device area of 2 × 10-5cm2at a dc biasing current density of 12 kA/cm2and ac voltage amplitude of 12 V. It is also found that, both output power values and efficiencies decrease with increasing enhanced leakage current.

Design considerations of high-efficiency double-drift silicon IMPATT diodes

High-efficiency silicon double-drift IMPATT diodes with a low-high-low doping profile structure are proposed. Devices with efficiencies of 25 percent for 12 GHz, 24 percent for 18 GHz, and 19 percent for 50 GHz, are Predicted by numerical calculations.

Shifting of the peak generation rate in double-drift silicon IMPATT diodes

In double-drift (DD) silicon IMPATT diodes, it is observed that the peak generation rates of both carriers (electrons and holes) lie within the n side. The shifting is due to the unequal ionization rates for electrons and holes in silicon. By neglecting the reverse saturation current, a simple analytical expression for the location where the peak generation occurs is derived. This simple result may be useful for the design of double-drift as well as complementary single-drift IMPATT diodes.

Millimeter-wave pulsed IMPATT diode oscillators

Double-drift silicon IMPATT diodes were fabricated for pulse source application at 35, 94, and 140 GHz. The diodes were operated with 300 ns pulsewidth and a 1.5 percent duty cycle. All sources exhibited a change in output frequency of >1 percent throughout the duration of the pulsewidth with <1 dB peak power variation. Peak pulse output power levels of 10, 2, and 0.7 W were achieved in each of the three frequency bands, respectively.

Improved performance of millimetre-wave impatt diodes on type-IIa diamond heatsinks

Thermal resistance and r.f. data are presented for Ka--, V and W-band silicon double-drift impatt diodes employing diamond heatsinks. A power level of 620 mW at 7.7% efficiency has been achieved at 101 GHz.

Pulsed Double-Drift Silicon IMPATT Diodes and Their Application

The performance and application of double-drift silicon IMPATT diodes designed for pulsed operation at frequencies between 8.5 and 18 GHz are described. Peak pulse powers greater than 18 W at 10 GHz and 13.5 W at 16.5 GHz were obtained for 800-ns pulses at a 25-percent duty cycle with the average junction-temperature, rise limited to 200/spl deg/C. Conversion efficiencies were between 11 and 13.7 percent. The microwave cavity and pulsed bias circuitry are described in detail.

Epitaxially grown double-drift silicon IMPATT diodes at 60 To 90 GHz

The characterisation of successively grown n- and p-type epitaxial layers suitable for double-drift 60-90 GHz oscillators is described. Microwave results are reported, and include 0.35 W with 9.2% efficiency at 70 GHz.

Ion-implanted double-drift Ka-band diodes

The application of a doubly charged boron (11B+2) beam to the formation of p-type drift regions in symmetrical K a -band double-drift silicon IMPATT diodes is discussed. Devices fabricated with these implanted impurity distributions exhibited output powers ∼1.2 W with 10-percent conversion efficiencies over the frequency range of 29 to 39 GHz.

Pulsed silicon double-drift IMPATTs for microwave and millimetre-wave applications

The letter describes silicon double-drift IMPATT diodes designed for operation at microwave and millimetre-wave frequencies. These devices have delivered pulsed-power outputs of 16 W with 12.3% efficiency in the X band, 11 W with 14% efficiency in the KU band, and 6.4 W with 5.3% efficiency in the Ka band. These results, when combined with the demonstrated high reliability of silicon IMPATTS, should lead to the wide application of double-drift devices in pulsed-radar systems.

X-band silicon double-drift IMPATT diodes using multiple epitaxy

Silicon double-drift IMPATT diodes made by consecutive epitaxial deposition have been fabricated successfully. Output power in excess of 1.7 W with 10-percent efficiency was obtained at X band.