Lucent Technologies Inc.

At+t Corp.

At&t Bell Laboratories

Tien-Heng Chiu

Alastair M Glass

Afshin Partovi

Keith Wayne Goossen

Won-Tien Tsang

John E Cunningham

Michael D Williams

A method is described for the preparation of a DFB/DBR laser which includes an electro-optic grating formed by periodically modulating the index of refraction of the cladding employed. The method involves depositing a waveguide upon a semi-insulating or doped substrate and then depositing an active layer upon the resultant structure. The active layer is subsequently selectively etched and a cladding material deposited adjacent thereto and electrically isolated therefrom. The cladding is then selectively patterned with a conductive material by photolithographic techniques to yield a grating to periodically modulate the index of refraction.

Method for fabrication of wavelength selective electro-optic grating for DFB/DBR lasers

An optical image correlator includes a photorefractive medium for recording an interference pattern that corresponds to the Fourier transform of an input image or the multiplicative product of the Fourier transforms of two respective input images. In contrast to correlators of the prior art, the correlator described here includes a semi-insulating, multiple quantum well device as the photorefractive medium.

High-speed optical image correlator

A novel substrate for growth of material by chemical phase deposition includes a temperature monitoring zone formed by applying a coating of growth preventing material (e.g., SiO.sub.x or SiN.sub.x) to a portion of the substrate. The temperature of the substrate can be monitored during growth of a desired material using an optical pyrometer having its field of view directed at the temperature monitoring zone.

Substrates and methods for gas phase deposition of semiconductors and

A spatial light modulator includes a multiple quantum well (MQW) device. Unlike MQWs of the prior art, this MQW is made semi-insulating. As a result, individual picture elements can be defined entirely by the placement of electrodes in an array on a surface of the device. Them is no need to etch trenches for electrical isolation of the picture elements.

Spatial light modulator using quantum well material

A device fabrication method includes an etching step for compound III/V semiconductor materials such as gallium arsenide or indium phosphide. The step is carried out in the chamber of a growth reactor under conditions that are compatible with a subsequent growth step performed in the same reactor. Specifically, etching is performed in a so-called pulsed mode wherein each etching interval is followed by an interval in which etching is interrupted. Moreover, a Group III species such as indium is introduced into the chamber during each etching interval to enhance the smoothness of the etched surface.

Method of fabricating a compound semiconductor device

This invention concerns with a non-alloyed ohmic contact to III-V semiconductor material in a III-V semiconductor device on a Si base. The ohmic contact includes at least one set of layers comprising a delta-doped monolayer and a thin layer of undoped III-V semiconductor material which is 2.5 nm or less in thickness, said at least one set of layers being upon a doped III-V semiconductor layer. An epitaxial layer of metal upon an uppermost of the layers of the said set of layers completes the ohmic contact, said metal being capable of wetting the surface of the III-V semiconductor material and of being epitaxially grown on the said III-V semiconductor material. At least the said at least one set of layers and the metal layer are deposited by Molecular Beam Epitaxy, thus avoiding formation of oxides and growing the metal epitaxially so that the metal layer is crystalline at least near the interface between the metal and the semiconductor material. The epitaxial deposition of the metal is conducted at a relatively low temperature of the semiconductor material. In an illustrative embodiment the metal is Al capable of being epitaxially deposited at a temperature within a range of from 10.degree. C. to 100.degree. C., preferably to a temperature ranging from 20.degree. C. to 50.degree. C., with 25.degree. C. being most preferable. The resultant contacts exhibit specific resistance which is lower and higher current passing capabilities which are higher than those of prior art non-alloyed ohmic contacts. However, the most noteworthy advantage of using Al in an integrated opto-electronic circuit comprising a III-V semiconductor device on a Si base, is the avoidance of 'purple plague'. The 'purple plague' may arise when gold-based contacts in III-V semiconductor devices and Al-based contacts in Si-devices being used in an integrated circuit come in contact, especially at higher, e.g. 300.degree. C., temperatures.

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Spotswood, NJ, United States of America

Tien-Heng Chiu