摘要:

An integrated approach to the understanding of charge-controlled electronic devices is presented. Although only vacuum triodes and diffusion-type transistors are discussed in detail, the methods suggested are also applicable to gas-filled and multi-electrode vacuum structures, to surface-barrier and to drift-type transistors, and to space-charge-limited solid-state devices. The treatment is tutorial in nature, and begins with the development of general equations of current flow applicable in any medium. The principles of charge-controlled devices are then summarized, and a general functional relationship between the total charge in transit and the transit time is developed. These results are then applied in turn to vacuum and semiconductor diodes and triodes to derive in a remarkably simple and consistent manner the salient features of their operation. ‘Ideal’ vacuum triode and transistor structures are first discussed, and the voltage and current amplification factors are then introduced as arbitrary parameters to account for practical departures from ideality. Specific results obtained are the d.c. characteristics and incremental equivalent circuits for each device. The model established for the transistor is identical with the hybrid-π circuit due to Giacoletto, and both low- and high-level injection conditions are included. Finally, it is suggested that the transistor collector saturation current with open base is a more fundamental quantity than that with open emitter, and the temperature dependence of the base-emitter voltage is shown to be linear at any injection level. Throughout, emphasis is on the principles involved and on the method of approach, and a particular effort is made to present the development of the vacuum and the semiconductor devices in a completely analogous manner.

DOI:10.1049/pi-b-2.1959.0166

出版商:IEE    

年代:1959

数据来源: IET

DOI:10.1049/pi-b-2.1959.0167

出版商:IEE    

年代:1959

数据来源: IET

摘要:

The recombination of excess carriers at the surface of a semiconductor depends on the surface potential in a bell-shaped manner (‘Stevenson-Keyes curve’). This holds in the case of silicon also if the surface is in contact with an electrolyte.To illustrate this dependence the recombination velocity is investigated by observing the photo-voltaic effect of ap-njunction alloyed to one surface of a thin silicon disc which is illuminated with non-penetrating light on the other side. The sensitivity of the photo effect is inversely proportional to the recombination velocity at the illuminated surface. If this surface is in contact with an electrolyte and if voltages of only a few tenths of a volt are applied between them, the sensitivity varies in a bell-shaped manner. The fact that the surface potential is influenced by the applied voltage can be proved by observing the surface photo effect between the silicon and electrolyte.

DOI:10.1049/pi-b-2.1959.0168

出版商:IEE    

年代:1959

数据来源: IET

摘要:

A survey of dominant recombination mechanisms in semiconductors is given in terms of elementary physical processes. A division between avoidable and unavoidable recombination mechanisms is convenient. In the former, group recombination through crystallographic defects and impurities, in the latter, group band-band Auger recombination, can be important. The evidence for the dominance of radiative recombination is rather limited.

DOI:10.1049/pi-b-2.1959.0169

出版商:IEE    

年代:1959

数据来源: IET

摘要:

The mechanisms of current through insulators in the presence of surface potential barriers and electron traps are discussed, and the simplified theory of space-charge-limited current through insulating solids is described. The steady-state equations for one-dimensional single-carrier current are derived and approximate solutions are given; theoretical current/voltage characteristics are calculated and indicate that large currents could flow and that their characteristics could be utilized in practical devices. The continuity equations for time-varying current are derived for the case when electron transit times and trapping relaxation times are both significant.Experiments are described which have demonstrated some of the predicted characteristics of space-charge-limited current; in particular a threshold voltage for current, a square-law dependence of current upon applied voltage, and rectification have been observed. The currents are of practical magnitudes; steady and reproducible current densities of several amperes per square centimetre have been drawn through insulating crystals of cadmium sulphide at room temperature with a few volts applied. Measurements with microsecond pulses have shown that there is no detectable delay by the crystal in responding to a pulse rise or fall time of the order of 0.1 microsec; there seems no fundamental reason why response times as short as 0.1 milli-microsec should not be expected.It is apparent that many new types of solid-state device may be developed by exploiting current in insulators. Some possible applications are discussed, including a dielectric triode which should combine the high input impedance of the vacuum triode with the high current output of the transistor and have a gain-bandwidth product as great as that of either device. The technical difficulties involved in developing space-charge-limited dielectric devices seem no greater than those successfully overcome in developing presently available semiconductor devices.

DOI:10.1049/pi-b-2.1959.0170

出版商:IEE    

年代:1959

数据来源: IET

摘要:

Recombination of electrons and holes may take place in the host crystal or at impurity centres, the energy being removed by radiation of a light quantum, by multiphonon emission, or by an Auger process. The probabilities for each of these six processes are discussed. While the lifetime in semiconductors is usually determined by multiphonon recombination at impurity centres, Auger recombination in the host crystal can be expected to dominate in small-band-gap crystals containing large concentrations of free carriers. Radiative recombination in the host crystal may limit the lifetime in semiconductors where band-to-band transitions are direct, provided that the specimens are reasonably free of recombination centres.

DOI:10.1049/pi-b-2.1959.0171

出版商:IEE    

年代:1959

数据来源: IET

摘要:

The paper seeks the approximate functional relationship between current amplification factor, α base width,w, and effective lifetime, τ of minority carriers in the base region of a transistor. In any set of observations this functional relationship may be obscured by variations in other parameters, so that statistical techniques must be used to eliminate their influence.The numerical calculations are based on the relationshipsα = α0−g(τ,w)= α0−h(τ,fαd) = α0−f(τ)wσwhereg,handfare functions of the effective lifetimes in the base region. The data to determineh(τ,fαd) were obtained from the curves of best fit to the scatter diagrams of α against 1/τ withfαc0constant. For the typical r.f. transistor under consideration the general relationshipα = α0− 0.21/fαd0.9τwas obtained; this is basically in agreement with that developed by Stripp and Moore.The paper examines the statistical method involved and its application to the particular problem. The measuring techniques are discussed in the light of possible errors and their compensation, and formulae are derived for σ andf(τ). The probable causes of the statistical spreads observed are reviewed and the results obtained are compared with the findings of Stripp and Moore.

DOI:10.1049/pi-b-2.1959.0172

出版商:IEE    

年代:1959

数据来源: IET

DOI:10.1049/pi-b-2.1959.0174

出版商:IEE    

年代:1959

数据来源: IET

DOI:10.1049/pi-b-2.1959.0175

出版商:IEE    

年代:1959

数据来源: IET

摘要:

The paper is concerned with the evaluation of transistors suitable for use as small-signal v.h.f. amplifiers. Parameters governing behaviour at very high frequencies are discussed and measurement techniques are described. Results of measurements at 100 Mc/s on two types of v.h.f. transistor are given; from these data, maximum available power gains are calculated and compared with values measured in a practical amplifier circuit.

DOI:10.1049/pi-b-2.1959.0176

出版商:IEE    

年代:1959

数据来源: IET