A family of microwave receivers is described which consists of antennas integrated with a balanced mixer and IF amplifier on a common substrate. Each receiver is small enough to enable two-dimensional arrays to be fabricated monolithically within a single semiconductor chip. The antenna pattern of each receiver is suitable for feeding via a dielectric immersion lens, thereby creating a high-gain array of beams in the far-field. Such receivers have been built to operate at 10 and 35 GHz, and show conversion loss similar to more conventional designs.

The design, modeling, and fabrication of a GaAs traveling-wave field-effect transistor (TWF) is reported. The TWF described is a device with a single continuous 1-µm-long gate and a total width of 3 mm which shows flat band gain from 1 to 10 GHz with the potential of much wider band performance (1-40 GHz) and high gains. An advanced theoretical model is presented which performs a full coupled transmission line modal analysis for three lines (source gate and drain) using ab.initio calculations of interelectrode capacitance and inductance matrices. Good agreement is demonstrated between theory and experiment for frequency gain response measurements using balanced feed circuits.

A theory has been developed for planar metal antennas on a dielectric surface and the main predictions have been verified experimentally. Current dipole antennas have radiation diagrams and impedances favourable for microwave to far-infra-red integrated circuits.

Computer simulations of Schottky barrier diodes show that electron heating occurs at high frequency as the depletion edge velocity increases. Mixer characteristics are reappraised in this light.

The importance of hot electron relaxation effects in semiconductor devices increases with frequency and, for the millimetre band, the transient processes have a major effect on their modes and terminal characteristics. A study of these effects provides a useful guide for practical device development. Relaxation effects are particularly strong in transferred-electron sources. The modes distort at high frequency and those most suitable for millimetre band generators are identified. In other sources and mixers relaxation effects are less dominant, but they have a significant influence on device philosophy above 100 GHz.

Computer simulations of overlength modes in transferred electron devices predict efficient second-harmonic-generator operation much less degraded by electron relaxation effects than for fundamental oscillators with the same output frequency.

A theory of noise in semiconductor devices is developed, expressing the intrinsic noise as the response of the electronic system to primary fluctuations of the electrons due to the statistical nature of the scattering events. The theory leads to a computational method complementing an existing technique for solving the Boltzmann equation for a device. The method is primarily aimed at noise in hot electron devices. It is applied to the transferred-electron amplifier, taking theoretical models of GaAs as definite examples and the predictions are compared with previous theory and experimental data.

Since 1970, InP has been developed as a material for microwave oscillators and amplifiers, with most interest to date being taken in transferred-electron devices. the physics of electron transport and of transferred-electron oscillators is reviewed; the features of greatest practical significance are the high potential oscillator efficiency set by the peak-to-valley ratio, which is approximately 3·5, of the velocity/field curve; studies of cathode-contact effects which have led to oscillator efficiencies over 20% and the observation of limited-space-charge-accumulation (l.s.a.) mode operation. Consideration is also given to other less developed InP microwave components, including transferred-electron small-signal amplifiers which have given noise measures of 8 dB at 15 GHz, and field-effect transistors for which encouraging preliminary results have been obtained.

The characteristics of accumulation transit oscillations in InP n+-n-n+ transferred-electron oscillators and the dependence of device efficiency on the injection properties of the cathode contact have been analysed by computer simulation.

Efficiencies of up to 21% at 11.0 GHz and 18.5% at 15.2 GHz have been obtained with InP transferred-electron oscillators with evaporated and alloyed cathode contacts made of oxidised Ag-Ga alloy.

The general characteristics of transferred-electron amplifiers predicted by a computer solution of the electron Boltzmann equation include the ratio of the maximum to the minimum operating frequency of approximately 3 and an intrinsic Q factor of about 1. The variation of the impedance function with the device parameters is discussed.

Simulations of overlength modes in InP transferred-electron devices indicate microwave conversion efficiencies greater than 25%. The maximum frequency of operation exceeds 20 GHz. but depends markedly on the nature of the electronic intervalley scattering processes and associated relaxation effects.

Simulations of n+-n-n+ GaAs devices show three régimes where the operating frequency substantially exceeds the normal transit frequency. The efficiency/frequency characteristics and the effects of length and carrier density differ from predictions for an idealised I.s.a. mode.

A device simulation method derived from a numerical method for solving the Boltzmann transport equation is described. It is essentially exact, in particular free from the assumption that electrons respond instantaneously to changes of electric field. A key feature is the representation of the k dependence of the free carrier distribution by an expansion in a set of basis functions. Reasonable accuracy can be obtained for a fairly small number of basis functions, leading to high computational efficiency compared with alternative exact simulation methods.

A numerical method for solving the Boltzmann equation for electrons in a semiconductor under spatially varying conditions has been used to investigate the characteristics of instabilities due to the transferred electron effect. For both accumulation layers and dipole domains the main features are in overall qualitative agreement with the predictions of existing theories, but in both cases electron relaxation effects are quantitatively significant in determining the velocities of the instabilities and their growth and decay characteristics.

physica status solidi (b)Volume 56, Issue 2 p. K93-K96 Short Note The Scattering Factor in n-Type InP C. Hilsum, C. Hilsum Royal Radar Establishment, Malvern, WorchestershireSearch for more papers by this authorH. D. Rees, H. D. Rees Royal Radar Establishment, Malvern, WorchestershireSearch for more papers by this authorW. Wilgoss, W. Wilgoss Royal Radar Establishment, Malvern, WorchestershireSearch for more papers by this author C. Hilsum, C. Hilsum Royal Radar Establishment, Malvern, WorchestershireSearch for more papers by this authorH. D. Rees, H. D. Rees Royal Radar Establishment, Malvern, WorchestershireSearch for more papers by this authorW. Wilgoss, W. Wilgoss Royal Radar Establishment, Malvern, WorchestershireSearch for more papers by this author First published: 1 April 1973 https://doi.org/10.1002/pssb.2220560252Citations: 7AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume56, Issue21 April 1973Pages K93-K96 RelatedInformation

A simulation method which efficiently solves the complete Boltzmann transport equation has been used to analyse transferred-electron oscillators. Four hitherto unrecognised relaxation effects have been identified, which are of major significance in characterising modes of operation.