Showing papers on "IMPATT diode published in 1992"

A generalized simulation method for MITATT-mode operation and studies on the influence of tunnel current on IMPATT properties

Abstract: A generalized method of DC and high-frequency analysis for microwave transit time diodes in mixed tunnelling and avalanche mode, which can be applied to any type of diode structure is reported. Taking a purely field-dependent tunnel generation rate for electrons, the same is computed for holes from a simulated energy band diagram within the depletion layer of the diode. The method has been applied to a variety of Si, GaAs and InP diode structures. The results show a substantial degradation of IMPATT properties due to phase distortion caused by the tunnelling current.

GaAs single-drift flat-profile IMPATT diodes for CW operation at D band

Abstract: Single-drift flat-profile GaAs IMPATT diodes were designed for CW operation in the 140 GHz range. The diodes were fabricated from MBE grown material, mounted on diamond heatsinks, and tested in a radial line full height waveguide cavity. An RF output power of 15 mW with a corresponding DC to RF conversion efficiency of 1.5 percent was obtained at 135.3 GHz.

Heterojunction IMPATT diodes

Abstract: Heterojunction IMPATT diodes, which incorporate an abrupt GaAs/Al/sub 03/Ga/sub 07/As p/N heterojunction in place of the standard p/n junction, have shown a number of significant properties that represent a considerable technological advance Ku-band experimental devices exhibit up to 20 dB higher power, superior DC characteristics, and 3-6 dB less phase noise content These and other properties are examined in detail, and a first-order theory of operation is proposed >

Low noise, high efficiency GaAs IMPATT diodes at 30 GHz

Abstract: Low noise, very high efficiency IMPATT diodes provide an attractive alternative to Gunn diodes for many millimetre-wave applications GaAs hi-lo single-drift IMPATT diodes are demonstrated The diodes are fabricated using molecular beam epitaxy and (at approximately 30 GHz) exhibit exceptional efficiencies (>20%), very low FM noise (-88 dBc/Hz at 100 kHz off-carrier) and simultaneous CW power levels in excess of 300 mW >

Analysis of planar millimeter wave slot antennas using a spectral domain approach

Abstract: Self-radiating oscillators in the millimeter wave range can be built by combining a slot resonator with an IMPATT diode. Good performance can be achieved only if the input impedance of the slot, seen at the terminals of the IMPATT diode, is in the proper range. The input impedance, obtained by a rigorous full wave analysis, is presented as a function of the slot width and substrate height for silicon and PTFE. It is shown that the required input resistance (typically is 2-5 Omega ) can be achieved by choosing narrow slots. The variation of the slot width allows an optimal matching of the resonator to the diode for any desired bias current. Comparison with a recently published self-radiating oscillator shows the validity of the simulation. >

Experimental studies on the electronic and mechanical tuning properties of resonant-cap IMPATT oscillators

Abstract: A detailed experimental investigation has been made on the electronic tuning of resonant-cap IMPATT oscillators at the X-band. The investigation is extended to include mechanical tuning properties, i.e. studies on the dependence of the tuning properties on the resonant-cap diameter and the cap height. The study of electronic tuning gives an interesting insight regarding tuning behaviour for various ranges of d.c. bias current. From the study of these tuning properties the optimum size of the resonant-cap cavity for realizing maximum power output and electronic tunability for a given IMPATT diode can be obtained, which would be useful in the design of resonant-cap IMPATT oscillators.

Silicon monolithic millimetre-wave integrated circuits

Abstract: Using silicon as the substrate material, silicon monolithic millimetre-wave integrated circuit (SIMMWIC) oscillators and receivers are successfully realised. For the coplanar oscillators, a slot is used as the resonant structure in which a monolithically integrated IMPATT diode, selectively grown by silicon molecular beam epitaxy (Si-MBE), acts as the negative resistance device. Pulsed and CW operation of the planar oscillators is achieved in the 90 GHz region. The output power is radiated directly from the resonant slot. Complete receivers, with monolithic Schottky diodes together with the antenna, are integrated on a single chip. The suitability of the chips for near-range measurements is pointed out. >

High efficiency, high power multiquantum well IMPATT device with optical injection locking

Abstract: Multiple quantum wells within an impact avalanche transit time device (IMPATT) utilizing a plurality of gallium arsenide/aluminum gallium arsenide heterojunctions are used to provide a high power, high frequency, high efficiency device operating at 50 GHz and up. The multiple quantum wells defined by the heterojunctions between pairs of gallium arsenide quantum wells and aluminum gallium arsenide barrier layers improves the nonlinearity of the avalanche process within the gallium arsenide quantum wells and reduces the ionization rate saturation limitations. Optical injection locking of the current through the IMPATT device is achieved by irradiating the active layer of the IMPATT device with modulated laser light.

New encapsulation modules for mm-wave GaAs transit-time devices

Abstract: A new encapsulation technique for GaAs transit-time devices in modules made of semi-insulating GaAs is reported. The modules, together with the active diode structure, were manufactured from one wafer by photolithographic processes. This technique offers possibilities for further reduction of the parasitics. First experimental results from modules with integrated IMPATT diode structures for V- and W-band frequencies are given.

Calculation of phase distortion due to tunnel injection in heterojunction IMPATTs

Abstract: A computer simulation method is suggested which uses the microwave negative resistance distribution profile within the depletion layer of an ATT device to calculate the phase distortion due to tunnel injected current. The method has been applied to explain the deterioration of device performance in GaAs/GaInAs heterostructure IMPATTs for high frequency operation.

Analytical expressions for the drift velocity of hot charge carriers in silicon

Abstract: Analytical expressions for the drift velocities of electrons and holes in Si have been reviewed. It has been found that these either do not fit with experimental data in an appreciable part of the high-field region with the desired accuracy or involve too many parameters. Simple drift velocity expressions, with only two parameters, which appear to be the best fit in the high-field range of 103−5 × 105 V cm−1, have been presented. The modification of the expression parameters has been discussed to fulfil the need for doped and higher temperature cases which are more common and practical in solid-state devices. These can be utilized for the modelling of Si devices such as the Impatt diode with simplicity and better accuracy.

Velocity modulation in GaAs/AlxGa1−xAs impact avalanche transit‐time diodes

Abstract: Velocity modulation using AlxGa1−xAs layers is, in principle, an attractive way of improving the efficiency of conventional GaAs impact avalanche transit‐time (IMPATT) devices. Critical to the concept, however, is a detailed understanding of the nature of high‐field electron transport in AlxGa1−xAs. We explore this via Monte Carlo simulations, with particular reference to the behavior found under nonuniform field conditions. Preliminary experimental results are presented for a simple, single‐drift IMPATT diode in which the drift region is made entirely from Al0.3Ga0.7As.

Simulation of the Diffusion Profile for Enhancement of Negative Resistance and Efficiency of Silicon Single Drift Region IMPATT Diodes

Abstract: The diffusion profile of a single drift region (SDR) p+nn+ silicon IMPATT diode is simulated using simple, generalized, and accurate computer methods for dc and small signal analysis of the diode for realizing high negative resistance and conversion efficiency at X-band (8 to 12 GHz). The results show that the optimized diffusion profile provides a junction depth of 0.83 to 0.86 μm with a surface concentration of 7.5 × 1025 to 1026 m−3. The optimized diode has a narrow avalanche zone with breakdown voltage of 89.3 V and conversion efficiency of 11%. The negative resistance and the negative conductance of the diode are also considerably enhanced due to optimization of the diffusion profile. Das Diffusionsprofil einer SDR (single-drift region)-p+ nn+ -Silizium-IMPATT-Diode wird mit einfachen, verallgemeinerten und genauen Computermethoden fur eine Gleichspannungs- und Klein-signalanalyse der Diode zur Realisierung eines hohen negativen Widerstands und Konversionswirkungs-grades im X-Band (8 bis 12 GHz) simuliert. Die Ergebnisse zeigen, das das optimierte Diffusionsprofil eine Ubergangstiefe von 0,83 bis 0,86 μm mit einer Oberflachenkonzentration von 7,5 × 1025 bis 1026 m−3 aufweist. Die optimierte Diode hat eine schmale Lawinenzone mit einer Durchbruchs-spannung von 89,3 V und einem Konversionswirkungsgrad von 11%. Der negative Widerstand und der negative Leitwert der Diode sind infolge der Optimierung des Diffusionsprofils ebenfalls betrachtlich erhoht.

Two-terminal millimetre wave devices

Abstract: The basic principles of RF-power generation in the millimetre wave range for two-terminal semiconductor devices are described. The most important devices, Impatt diode and Gunn element, as well as less known structures like Baritt, Mitatt, Tunnett, PIN-avalanche, double-barrier, and Qwitt are presented. The limitations in output power and efficiency for elevated millimetre wave frequencies are discussed and rf-power, conversion efficiency, and noise behaviour of the different devices are compared.

Microwave Vacuum Tube and Solid State Sources

Abstract: With solid state devices, it is possible to generate microwave power from microwave transistors, gunn diodes and Impatt devices. However, for high power, high frequency and wide bandwidth applicati...

Semiconductor component mfr. esp. IMPATT diode prodn. - producing component, housing and connection contacts in integrated construction from and on semiconductor substrate

Abstract: The semiconductor substrate (1) is structured on both sides. At least one semiconductor component (11) is produced on the front face of the substrate. Two bonding areas (8,9a,9b) for the associated housing are arranged on each side of the component. Photolithographic and etching processes are used to remove the rear side of the semiconductor substrate below the component, and contact strips (15) are formed from the upper edge of the rear of the substrate to the component. Between the component and the bonding areas, the substrate is removed such that the substrate below the bonding areas remains and distancing pieces and a thin strut are formed, the contact strips being partially uncovered. USE/ADVANTAGE - Also for BARRIT diodes. Enables semiconductor components with housings having very small dimensions to be produced using simple process steps. Both process yield and reliability are increased.