Publisher Summary This chapter examines the signal and noise properties of gallium arsenide (GaAs) microwave field-effect transistors (FET) High frequency gallium arsenide field-effect transistors (GaAs FETs) have demonstrated remarkably low noise figures and high power gains at microwave frequencies A practical microwave GaAs FET is usually fabricated by deposition or diffusion of source, gate, and drain contacts on the surface of an appropriately doped thin epitaxial n-type layer This layer, in turn, is grown on a semi-insulating wafer by either a vapor or liquid epitaxial technique The apparent minor role played by the negative resistance region in practical short-gate FETs suggests that radiofrequency instabilities due to this region, if they exist, occur at frequencies far above the normal frequency regime of microwave FETs The small-signal equivalent circuit of the FET, valid up to moderately high frequencies is elaborated It is found that noise in a microwave GaAs FET is produced both by sources intrinsic to the device and by thermal sources associated with the parasitic resistances

Signal and Noise Properties of Gallium Arsenide Microwave Field-Effect-Transistors

In this paper we discuss the discrete Fourier transform and point out some computational problems in (mainly) complex analysis where it can be fruitfully applied. We begin by describing the elementary properties of the transform and its efficient implementation, both in the one-dimensional and in the multi-dimensional case, by the reduction formulas of Cooley, Lewis, and Welch (IBM Res, paper, 1967).The following applications are then discussed: Calculation of Fourier coefficients using attenuation factors; solution of Symm’s integral equation in numerical conformal mapping; trigonometric interpolation; determination of conjugate periodic functions and their application to Theodorsen’s integral equation for the conformal mapping of simply and of doubly connected regions; determination of Laurent coefficients with applications to numerical differentiation, generating functions, and the numerical inversion of Laplace transforms; determination of the “density” of the zeros of high degree polynomials. We then...

Fast Fourier Methods in Computational Complex Analysis

A review of recent and current work on microwave FET's and amplifiers is presented, and an extensive bibliography of recent articles is appended (250 references). First, the various FET structures (MRSFET's, JFET's, and IGFET's) and their performances are reviewed. Second, the principle of operation is outlined for Si- and GaAs-MESFET's; the basic device physics, equivalent circuit, high-frequency limitations, and noise behavior are treated. Third, the design principles and performance of microwave MESFET amplifiers are summarized.

Microwave Field-Effect Transistors--1976

The results of computer simulations of submicron-scale Si and GaAs MESFET's which include carrier energy transport effects ("velocity overshoot") are presented. A new technique for solving the energy transport equation, which allows the description of short-time-scale carrier dynamics to be greatly improved without significantly increasing program complexity or computer time relative to conventional numerical simulations is described. The results indicate that the switching times of GaAs MESFET's should be less than would be predicted by conventional numerical models, and are consistent with experimental results.

Two-dimensional numerical simulation of energy transport effects in Si and GaAs MESFET's

The onset of gate-drain avalanche imposes an important fundamental constraint on the drain voltage swing, and hence, on the output power of GaAs FET's. In this paper we show that recognition of the role of surface depletion and proper attention to channel design can yield avalanche voltage factors of 2-3 above bulk values. The appropriate design strategy is minimization of the undepleted epitaxial charge per unit area (Q u ) between gate and drain, which, in turn, dictates a gate-notch depth approximately equal to the surface zero-bias depletion depth. A simple lateral spreading model is proposed which predicts that V_{L} \sim 50Q\min{u}\max{-1} , where V L is the gate-drain avalanche voltage and Q u is measured in units of 1012electrons/cm2. This prediction is supported by a large body of experimental dc and pulse data, although considerable scatter is observed which we have attributed to epi charge nonuniformities, premature avalanche at the rough edges of AI gates formed by a liftoff process, and surface charging variations associated with dielectric passivation. The observed dependence of V L on epi charge rather than on doping level, as predicted for bulk avalanche, provides convincing evidence for nonbulk two-dimensional avalanche in the thin-film ( Q_{u} ) FET geometry. In thick films ( Q_{u} > 2.6 ), on the other hand, it is found that the bulk avalanche predictions are reasonably accurate. In terms of saturated epi current I s , the bulk regime corresponds to I_{s} > 450 mA/mm and the lateral spreading (thin-film) regime to I_{s} mA/mm. Finally, we have found that gate-drain avalanche is the major cause of output saturation as a function of drain potential in power GaAs FET's.

Control of gate&#8212;Drain avalanche in GaAs MESFET's

This letter describes a numerical analysis of substrate effects in j.f.e.t.s. It is shown that the addition of a high-resistivity substrate increases the output conductance considerably, whereas the transconductance is not much affected. The substrate behaves roughly like a parallel resistor.

Two-dimensional analysis of substrate effects in junction f.e.t.s

The electrical properties of f.e.t.s with submicrometre gates are investigated by means of a 2-dimensional computer model. It is found that the gain-bandwidth product increases with decreasing gate length and reaches a value of 70 GHz for 0.1 ?m gates. This improvement is, however, at the expense of open-circuit voltage gain. A practical limit of the gate length for useful devices is found to be about 0.1 ?m.

Computer study of submicrometre f.e.t.s

The letter describes the solution of the instationary semiconductor transport equations by means of finite-difference methods. This new approach is based on the formal similarity with the equations of incompressible flow. Implicit schemes have proven useful for the computation of both transient and steady-state solutions. Comparisons with experimental results are extremely favourable for f.e.t.s.

Difference methods for the solution of the time-dependent semiconductor flow equations

A microscopic-scattering particle model is described that combines a 2-dimensional spatial representation of the fields with a 2-band Monte Carlo description of the scattering events. A simplified scattering law produces a particle model for the diffusion approximation. Results are shown for Si and GaAs f.e.t.s and a GaAs diode.

Two-dimensional particle models in semiconductor-device analysis

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

M. Reiser

Author Tools

Chat about Author

Papers

Two-dimensional analysis of substrate effects in junction f.e.t.s

Computer study of submicrometre f.e.t.s

Difference methods for the solution of the time-dependent semiconductor flow equations

Two-dimensional particle models in semiconductor-device analysis