Bell Telephone Laboratories

At&t Bell Laboratories

American Telephone & Telegraph Co., At&t Bell Laboratories

At&t Technologies, Inc.

Paul A Kohl

Frederick W Ostermayer, Jr

Stephen R Forrest

Catherine Wolowodiuk

Harvey S Trop

Reginald R Buckley

Jeffrey R Bessette

Alastair M Glass

Yusuke Ota

Lucian Arthur D'Asaro

Lawrence Edwin Smith

Tien P Lee

Michael G Brown

Charles A Burrus, Jr

Richard L Panock

Duane E Bacon

Richard M Lum

Randolph H Burton

Daniel R Kaplan

Linear arrays of optical fibers are aligned to linear arrays of optoelectronic devices (e.g., photodiodes, diode lasers or LEDs) formed on an elongated chip. The alignment procedure results in a subassembly which includes fiber segments embedded between V-groove mounting blocks and the device array chip affixed to an end face of the blocks.

Aligning arrays of optoelectronic devices to arrays of optical fibers

A process is described for making semiconductor lasers with cleaved facets for end mirrors. The process involves electrochemically photoetching slots with deep, narrow cross-sections in a wafer and applying stress to cleave the wafer in the desired place. Extremely short and reproducible semiconductor lasers can be made by this procedure (less than 50 or even 25 .mu.m) which yields extremely useful semiconductor lasers particularly for communication applications. Also, the procedure requires a minimum of skill to produce excellent quality cleaved semiconductor lasers (including short-length lasers) with high yields.

Fabrication of cleaved semiconductor lasers

A photoelectrochemical etching process is described for producing gratings in various semiconductors. Because this is a direct, single step process, extreme uniformity is obtained over a wide area. The procedure is particularly useful for mode reflection in distributed feedback lasers.

Process of producing devices with photoelectrochemically produced

Photoelectrochemical etching of gallium arsenide in highly alkaline aqueous solution yields optically smooth etched surfaces suitable for many optical devices. Higher optical quality is obtained for lower irradiation energy provided sufficient energy is available to produce holes in the valence band.

Etching optical surfaces on GaAs

A process is described for photoelectrochemically etching n-type gallium arsenide and closely related compound semiconductors such as gallium aluminum arsenide and gallium arsenide phosphide. Such a process is advantageous because the etching is confined to where light is incident to the surface of the semiconductor. In addition, the shape of the configuration etched out of the semiconductor can be controlled by the light incident on the surface of the semiconductor. For example, undercutting can be minimized by use of parallel rays incident on the surface of the semiconductor to be etched.

Photoelectrochemical etching of n-type gallium arsenide

Photoelectrochemical processing of semiconductors is highly desirable because of its versatility and simplicity. The invention is a photoelectrochemical etching procedure for n-type silicon in which an alcohol based solution of hydrofluoric acid is used as the electrolyte. This procedure is useful for the fabrication of a variety of silicon devices.

Photoelectrochemical etching of n-type silicon

A process is described for plating silver on metallic surfaces electrically attached to a compound semiconductor. This process involves a photoelectrochemically induced oxidation reaction in which the compound semiconductor is oxidized and reduction to metallic silver takes place on the metallic surface electrically connected to the semiconductor. This procedure is particularly valuable where silver is to be plated in small holes or crevices in the semiconductor structure. It is particularly valuable because plating is specific to the metallic surface and does not occur on the semiconductor surface. It is useful in providing low inductance electrical connections to various parts of semiconductor devices such as in the source for gallium arsenide field effect transistors. Silver is particularly valuable in such applications because of its chemical inertness, high electrical conductivity and exceptionally high thermal conductivity which permits high transistor power handling capabilities.

Photoelectrochemical plating of silver

An etching process is described which can etch geometrical shapes on the surface of an n-type or intrinsic compound semiconductor and yield surfaces of optical quality without further processing. The etching process is an electrochemical process where etching is proportional to light intensity. The process involves applying a potential to the compound semiconductor while immersed in an electrolytic solution and irradiating the surface to be etched with light in a certain energy range. The electrolytic solution contains hydrofluoric acid. The distribution of light intensity and ray direction is selected to produce the desired geometrical shape. Particularly advantageous is that the surfaces produced are of optical quality. For example, lenses produced by the etching process exhibit surfaces of optical quality. Further, the process can be carried out on all the lenses on a wafer simultaneously without attention to individual devices. This is highly desirable economically. Also, the lenses produced are integral parts of the light emitting diode.

Etching of optical surfaces

A procedure is described for electrochemically photoetching n-type and intrinsic compound semiconductors. The process involves applying a potential to the compound semiconductor while it is in contact with an electrolytic solution and irradiating the surface to be etched with light in a certain energy range. By suitable adjustment in the potential, electrolytic solution composition and light energy, the etch rate is made proportional to the light intensity. By suitable variation in light intensity and light-ray direction, various geometrical features can be made on the surface of the compound semiconductor. For example, a hole with straight sides can be made in the compound semiconductor by use of a light spot and parallel (collimated) light rays. An advantageous application of this process is the fabrication of a photodiode with a hole in the center for use in bidirectional communication systems and to monitor power output for optical communication sources. The advantage of this process is that no damage occurs outside etched hole so that a maximum area of the photodiode remains active for detecting incoming radiation. Another advantage of the process is that etching will stop where the material becomes p-type so that etching can be made to stop automatically at a p/n junction.

Electrochemical photoetching of compound semiconductors

A photoelectrochemical process is described for anisotropic etching of intrinsic III-V compound semiconductors. Such a process is highly advantageous because the etching takes place only where light is incident on the surface of the semiconductor. Thus, various patterns can be etched into the semiconductor surface without the use of a mask, undercutting is minimized where masks are used and the shape of the hole etched out of the surface can be controlled.

Photoelectrochemical processing of III-V semiconductors

A process is described for plating gold on metal surfaces electrically attached to a compound semiconductor. The procedure is particularly valuable where gold is to be in small holes or crevices in semiconductor structure since electroplating on the semiconductor surface is avoided. The process is useful for providing low inductance electrical connection to various parts of semiconductor devices such as to the source in gallium arsenide field-effect transistors.

Photoelectrochemical gold plating process

A process is described for photoelectrochemically etching n-type indium phosphide and closely related compound semiconductors such as indium gallium arsenide and indium gallium arsenide phosphide. Such a process is advantageous because the etching is confined to where light is incident to the surface of the semiconductor. In addition, the shape of the configuration etched out of the semiconductor can be controlled by the light incident on the surface of the semiconductor. For example, undercutting can be minimized by use of parallel rays incident on the surface of the semiconductor to be etched.

Photoelectrochemical processing of InP-type devices

An electroplating process is described for plating various metals and alloys in which certain organic substances are added to the plating solution. This permits high plating rates with excellent plating results, including smooth bright finishes, freedom from dendritic growth and constant plating thickness over wide areas.

Electroplating zinc

A gold electroplating bath comprising heterocyclic organic compounds such as lactones, lactams, cyclic sulfate esters, cyclic imides and cyclic oxazolinones.

Electrolytic gold plating

A silver electroplating bath comprising heterocyclic organic additives such as lactones, lactams, cyclic sulfate esters, cyclic imides and cyclic oxazolinones, preferably phenolphthalein.

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Chatham, NJ, United States of America

Paul A Kohl