Societe Anonyme De Telecommunications

Sat (societe Anonyme De Telecommunications)

Sat Corporation

Michel Royer

Alain R Durand

Yves Carpentier

Jean G Besson

Robert Triboulet

Michel B Sirieix

Gerard Didier

Andre A Salaville

Jean-Luc Dessus

An HgCdTe avalanche photodiode for use at ambient temperature comprises an Hg.sub.1-x Cd.sub.x Te crystal substrate in which x is chosen between substantially 0.35 and substantially 0.5, a PN junction is formed in the substrate with low concentrations in the vicinity of the junction, by impurity penetration from a polished and chemically etched surface and the P zone is illuminated. A guard band is provided around the PN junction. The dark current of the photodiode is less than 0.1 .ANG./cm2 at ambient temperature and the excess noise factor is less than 0.4. The photodiode of the invention is used for detecting signals transmitted along fluorated glass optical fibers, for example.

HgCdTe avalanche photodiode

A method is disclosed for preparing a crystalline ingot of Hg.sub.1-x.sbsb.o Cd.sub.x.sbsb.o Te. Before moving a heated solvent zone for progressively dissolving ingot sources and giving rise to a single ingot, an adaptation zone is created from a monocrystalline germ by heating and cooling the solvent in contact with the germ, the ingot obtained is monocrystalline. The method of the invention in particular reduces the manufacturing costs of components such as infrared detectors and avalanche diodes.

Method of preparing a crystalline ingot of Hg.sub.1-x.sbsb.o

Process for preparing crystals of Hg.sub.1-x Cd.sub.x Te, in which ingots of HgTe and of CdTe are made to pass through a solvent zone, characterized in that it comprises the step of using as solvent a mixture of tellurium, of HgTe and of CdTe in proportions corresponding to thermodynamic balance.

Process for preparing crystals of Hg1-x Cdx Te

The device includes at least two diode arrays which contain some diodes which are defective. The defective diodes are compensated in that the respective diodes of the two arrays are aligned in pairs along the scanning direction, with each of the pairs containing at least one good diode. The device also comprises a programmed memory for controlling two switches and for accomplishing a winding or serpentine readout of the arrays. The device is well adapted for landscape scanning.

Photovoltaic diode detection device having compensation for defective

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Paris, France

Michel Royer