Hardening electronic devices against very high total dose radiation environments

The possibilities and limitations of hardening silicon semiconductor devices to the high neutron and gamma radiation levels and greater than 10 to the eighth power rads required for the NERVA nuclear engine development are discussed. A comparison is made of the high dose neutron and gamma hardening potential of bipolar, metal insulator semiconductors and junction field effect transistors. Experimental data is presented on device degradation for the high neutron and gamma doses. Previous data and comparisons indicate that the JFET is much more immune to the combined neutron displacement and gamma ionizing effects than other transistor types. Experimental evidence is also presented which indicates that p channel MOS devices may be able to meet the requirements

Selected problems in semiconductor physics and electronic devices

This book presents a set of solved examples on semiconductor device physics. Semiconductordevices is a core subject in electrical engineering and physics curricula. The level of the proposedexamples corresponds to a semester course at senior undergraduate or junior graduate level.Readers are expected to have a basic background on quantum and solid state physics, moreovera reasonable mathematical knowledge reaching differential equations is also assumed.2019/202

Electron Spin for Classical Information Processing: A Brief Survey of Spin-Based Logic Devices, Gates and Circuits

In electronics, information has been traditionally stored, processed and communicated using an electron's charge. This paradigm is increasingly turning out to be energy-inefficient, because movement of charge within an information-processing device invariably causes current flow and an associated dissipation. Replacing charge with the "spin" of an electron to encode information may eliminate much of this dissipation and lead to more energy-efficient "green electronics". This realization has spurred significant research in spintronic devices and circuits where spin either directly acts as the physical variable for hosting information or augments the role of charge. In this review article, we discuss and elucidate some of these ideas, and highlight their strengths and weaknesses. Many of them can potentially reduce energy dissipation significantly, but unfortunately are error-prone and unreliable. Moreover, there are serious obstacles to their technological implementation that may be difficult to overcome in the near term. This review addresses three constructs: (1) single devices or binary switches that can be constituents of Boolean logic gates for digital information processing, (2) complete gates that are capable of performing specific Boolean logic operations, and (3) combinational circuits or architectures (equivalent to many gates working in unison) that are capable of performing universal computation.Comment: Topical Revie

DC and AC modeling of heterostructure bipolar transistors (HBTS)

Starting with a homojunction or graded heterojunction bipolar transistor, a complete model for the dc and ac performances of the device is developed based on the Ebers-Moll methodology. The formulation is modified to include the abrupt single HBT, by introducing the effects of the conduction band discontinuity at the base-emitter junction as an energy barrier for electrons flow resulting in transmission and reflection processes. Finally, using the same approach, the formulation is extended to the abrupt double HBT. The collector current as a function of collector-emitter voltage, the collector and base currents as a function of base-emitter voltage, the dc current gain as a function of collector current, the h parameters as a function of collector current, the ac current gain as a function of frequency, and finally the unity current gain cut-off frequency as a function of the collector current are calculated for various graded and abrupt, single and double AlGaAs/GaAs HBTs. The results are in good agreement with the reported data

GaAs optoelectronic neuron arrays

A simple optoelectronic circuit integrated monolithically in GaAs to implement sigmoidal neuron responses is presented. The circuit integrates a light-emitting diode with one or two transistors and one or two photodetectors. The design considerations for building arrays with densities of up to 10^4 cm^-2 are discussed

Characteristics of UHF transistors using autoregistered structures

The basis of a novel bipolar transistor structure was proposed by Dr R. Aubusson of Middlesex Polytechnic in 1977. The novelty lies in replacing the conventional overlay transistor's P+ base grid with a refractory metal grid, in order (a) to lower the base resistance and (b) to autoregister the emitter. It was claimed that the linearity of the transistor would also be improved. A number of questions raised by this idea have been investigated, the methods and conclusions of which are presented here. Plausible structures, using the metal base grid, are proposed and compared with conventional structures. Some advantages are seen to be possible. The current understanding of distortion analysis applied to transistors is reviewed. The main ideas are presented in a unified manner and are extended to higher order. A number of the transistor's second order effects are analysed in a novel fashion. The metal base grid transistor is analysed and compared with conventional transistors, with favourable results. Practical aspects of fabricating the metal base grid transistor were investigated. A procedure for deposition has been determined and is presented here along with the film physical and electrical characteristics. Analysis of the tungsten-silicon interface shows the suitability of the metallization as a base grid. Suitable means of delineating the tungsten film have been assessed and a working procedure determined. Subsequent deposition of various insulators has been investigated and the problems associated with the readily oxidized tungsten film have been overcome. Formation of the emitter, requiring further high temperature processing, has been assessed in view of the limitations imposed by the preformed base metallization. In summary, it has been shown that the novel structure can be constructed and that significant performance improvement is to be expected, although a full realization was not possible within the resource constraints of the project

The AlInP material system in heterojunction bipolar transistor technology

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1994.Includes bibliographical references (leaves 70-71).by Ayça Yüksel.M.S