Thomson-csf

Paul C Moutou

Michel Hareng

Jacques Montel

Serge Le Berre

Jean-Pascal Duchemin

Jean-Jacques Godart

Pierre Gibeau

An electrically controlled visualization device comprising an electrochromatic material placed between a first electrode and a second electrode, said electrodes being supported respectively by two plates at least one of which is transparent, and said electrodes being connected to a voltage source adapted to produce a displacement of ions by diffusion which modifies the aspect of the said material, wherein an electric heating current passes through one of said electrodes, the duration of the application of said voltage being selected in such as a manner that said displacement is dependent on said current.

Thermoelectrically controlled electrochromatic visualization device

A semiconducting diode utilizing the transit time of electrical charge carriers in a semiconductor medium, having an input structure formed by a matrix of micropoints, said matrix consisting of a plurality of microscopic contacts separated by an insulating layer. The diameter of each contact is of the order of 0.5 to 5 micrometers, the distance between the closest contacts being of the order of 0.5 to 15 micrometers. The contacts are made of metal or of an alloy of low resistivity or of a semiconductor material generally doped more heavily than the layer of the semiconductor lying under the microscopic contact. The result of such a structure is an increase in efficiency attributable to the reduction in avalanche voltage or to a better injection by tunnel effect.

Transit time diode with an input structure formed by a matrix of

A method for virtually eliminating contact resistances in particular at very high frequency, for instance in the case of source and drain contacts of a field effect transistor. The method consists in creating a matrix of depressions or 'dishes', for example 1 to 6 microns in diameter, separated by intervals of some few microns. In a first step, windows are opened in an insulating layer by an etching operation. In a second step, by ion machining, angular profiles are carved in the bottom of the dishes for promoting tunnel effect. In a last step a metal layer is deposited and enshrouds the matrix.

Method of manufacturing metal-semiconductor contacts exhibiting high

A junction-type field-effect structure has an active layer covered at least in part by a dielectric layer. A metal base is applied to the dielectric layer.

Field-effect structures

In a Gunn effect device the cathode contact is formed by an assembly of zones through which is effected the injection of current adjoining an assembly of zones which on the contrary are capable of blocking this injection. A layer of dielectric material possibly insulates these two types of zones. A metallic control electrode assures the arrival of the current. The respective dimensions of these zones are determined in such manner that, in operation, the injected current is channeled between parts of the device made dielectric by the creation of space charges.

Hyperfrequency device with gunn effect

This invention relates to apparatus for automatically tracing patterns under the control of a program recorded in a computer. Said apparatus comprises means for initially recording the pattern in a liquid crystal cell by a known method under the control of said computer, and means for projecting the pattern thus recorded onto a photosensitive surface which records it on a reduced scale. It may also be projected on a large scale onto a monitor screen.

Optical pattern tracer

The method relates to the production of a very thin insulating or weakly-doped layer in the immediate neighborhood of a highly-doped layer within the body of a semiconductor structure designed to operate in the microwave range. For instance a P.sup.+ I N.sup.+ structure is obtained in an N.sup.+ -doped gallium arsenide substrate, by implanting a P.sup.+ - layer using beryllium ions. An insulating layer is spontaneously formed between the highly-doped layers. Using beryllium, the thickness is effectively of the order of one-tenth of a micron. In another example, an avalanche diode of high efficiency, made of gallium arsenide for microwave operation, having a P.sup.+ N.sup.- N.sup.+ N N.sup.+ structure is obtained wherein the layer N.sup.- is the thin weakly-doped layer in the immediate neighborhood of a highly-doped layer (N.sup.+), which is substantially as thin as the N.sup.- layer in this particular case.

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Paris, France

Paul C Moutou