Texas Instruments Corporation

Drs Fpa, L.p.

Raytheon Company

L-3 Communications Corporation

Raytheon Ti Systems, Inc.

John H Tregilgas

Herbert F Schaake

Jeffrey Don Beck

Arthur Monroe Turner

Michael A Kinch

Donald F Weirauch

Thomas W Orent

Bruce E Gnade

Howard R Beratan

Richard Lee Knipe

Roland W Gooch

Charles M Hanson

Thomas R Schimert

Athanasios John Syllaios

Chang-Feng Wan

Dipankar Chandra

Thomas L Polgreen

Sidney G Parker

Hidekazu Yoshihara

Kevin Soch

Walter L Kriss

John A Dodge

Systems and methods for solder bonding that employ an equilibrium solidification process in which the solder is solidified by dissolving and alloying metals that raise the melting point temperature of the solder. Two or more structure surfaces may be solder bonded, for example, by employing heating to melt the solder and holding the couple at a temperature above the initial solder melting point of the solder until interdiffusion reduces the volume fraction of liquid so as to form a solid bond between surfaces before cooling to below the initial melting point of the solder.

Systems and methods for solder bonding

An infrared detector ( ) includes a substrate ( ) having thereon an array of detector elements ( ). Each detector element has a membrane ( ), which includes an amorphous silicon layer ( ) in contact with at least two electrodes ( ) that are made of a titanium/aluminum alloy which absorbs infrared radiation. In order to obtain a desired temperature coefficient of resistance (TCR), the amorphous silicon layer may optionally be doped. The effective resistance between the electrodes is set to a desired value by appropriate configuration of the electrodes and the amorphous silicon layer. The membrane includes two outer layers ( ) made of an insulating material. Openings ( ) may optionally be provided through the membrane.

Infrared detector with amorphous silicon detector elements, and a method of making it

A method of gettering impurities from substrates (304) such as CdTe and CdZnTe by formation of liquid droplets (306) of a lower melting point material such as Cd or Te on the substrate during an anneal. The droplets may form from the melting of a thin layer of the material which had been deposited on the substrate (304). A subsequent mechanical removal of the cooled and solidified droplets also removes the gettered impurities.

Method of impurity gettering

A hybrid focal plane array has Hg.sub.1-x Cd.sub.x Te junction photodiodes formed in a substrate of HgCdTe which is capped by a layer of Te-rich CdTe. Type conversion of a low metal vacancy HgCdTe substrate to p-type is performed by annealing the capped substrate at a temperature sufficient to support interdiffusion between the Te-rich CdTe capping layer and the HgCdTe substrate. Use of the CdTe capping layer with a slight excess Te maintains the surface of the HgCdTe substrate in a Te-rich phase condition.

Intrinsic p-type HgCdTe using CdTe capping layer

Method of producing intrinsic p-type HgCdTe using CdTe capping layer

A method is provided for producing an n-type or p-type epitaxial layer using a doped substrate material. The method includes growing a substrate (12), preferably from a material to which an epitaxial layer can be lattice-matched. The substrate (12) is doped with a predetermined concentration of dopant (14). Preferably, the dopant (14) possesses the ability to rapidly diffuse through a material. An epitaxial layer (16) is grown upon the doped substrate (12). The epitaxial layer (16) and the doped substrate are annealed, thereby causing the dopant (14) to diffuse from the substrate (14) into the epitaxial layer (16).

Method for doping epitaxial layers using doped substrate material

A P-type substrate for infrared photo diodes can be produced by the present invention. A CdZnTe substrate is utilized. A first layer of HgCdTe is formed by liquid phase epitaxy on the substrate. A CdTe passivation layer is formed over the HgCdTe. A ZnS layer is formed over the CdTe layer. A noble metal is introduced into either the CdTe or ZnS layers. During a subsequent baking of the composite, the noble metal diffuses throughout the composite and into the HgCdTe layer.

Noble metal diffusion doping of mercury cadmium telluride for use in

An electrically addressable, integrated, monolithic, micromirror device (10) is formed by the utilization of sputtering techniques, including various metal and oxide layers, photoresists, liquid and plasma etching, plasma stripping and related techniques and materials. The device (10) includes a selectively electrostatically deflectable mass or mirror (12) of supported by one or more beams (18) formed by sputtering and selective etching. The beams (18) are improved by being constituted of an impurity laden titanium-tungsten layer (52) with an impurity such as nitrogen, which causes the beams to have lattice constant different from TiW. The improved beams (18) exhibit increased strength, and decreased relaxation and creep.

Micromechanical device having an improved beam

A hybrid focal plane array has p-n junction photodiodes formed in a substrate (10) of HgCdTe which is passivated by a cap layer (12) of Cd-rich CdTe. The active surface of the HgCdTe substrate is passivated by annealing at a temperature sufficient to support interdiffusion between the Cd-rich CdTe capping layer (12) and the HgCdTe substrate (10). Use of the CdTe capping layer (12) with a slight excess Cd maintains the surface of the HgCdTe substrate (10) in a metal-rich phase condition.

Method using cadmium-rich CdTe for lowering the metal vacancy

An electrically addressable, integrated, monolithic, micromirror device (10) is formed by the utilization of sputtering techniques, including various metal and oxide layers, photoresists, liquid and plasma etching, plasma stripping and related techniques and materials. The device (10) includes a selectively electrostatically deflectable mass or mirror (12) of supported by one or more beams (18) formed by sputtering and selective etching. The beams (18) are improved by being constituted of an electrically conductive, intermetallic aluminum compound, or a mixture of two or more such compounds. The materials constituting the improved beams (18) have relatively high melting points, exhibit fewer primary slip systems than FCC crystalline structures, are etchable by the same or similar etchants and procedures used to etch aluminum and aluminum alloy, and are stronger and experience less relaxation than aluminum or aluminum alloys. Accordingly, the improved beams (18) exhibit increased strength, and decreased relaxation without requiring significant or radical deviations from the typical processing steps employed to produce the otherwise unaltered device.

Methods of annealing Hg.sub.1-x Cd.sub.x Te slices (56) in a mercury reflux chamber (32, 34) with a mercury reservoir (52) at the bottom and condensation regions at the top (62) is disclosed. The chamber is heated by a furnace (44) that creates an annealing region encompassing both the reservoir and a holder (46) for the Hg.sub.1-x Cd.sub.x Te slices (56). In preferred embodiment methods reservoir (52) is heated to 270.degree. C. for two hours to sixty days. An annealing immediately after LPE growth by use of either mercury vapor from the melt or a separate reservoir is also disclosed.

Reflux annealing device and method

The disclosure relates to a method of forming samples of alloys of group II-VI compositions having minimum dislocations, comprising the steps of providing a sample of a group II-VI compound, providing an enclosed ampoule having the sample at one end portion thereof and a group II element of the compound at an end portion remote from the one end portion, heating the sample to a temperature in the range of 350 to the melting temperature of the compound for about one hour while maintaining the group II element at a temperature more than 200.degree. C. below the sample temperature, heating the group II element to a temperature from about 5.degree. to about 50.degree. C. below the temperature of the sample while maintaining the sample at a temperature in the range of 350.degree. to 650.degree. C. both of about 15 minutes to about 4 hours, and then stoichiometrically annealing the sample at a temperature below 325.degree. C.

Method of preventing dislocation multiplication of bulk HgCdTe and LPE

A three step annealing treatment for Hg.sub.1-x Cd.sub.x Te includes a high temperature anneal to reduce excess tellurium, followed by an intermediate temperature anneal to reduce the supersaturation of metal vacancies, and lastly a low temperature anneal to reduce metal vacancies; see FIG. 4. The intermediate anneal reduces the metal vacancy concentration sufficiently that microvoids do not form from condensation of metal vacancies in desired portions of the Hg.sub.1-x Cd.sub.x Te during the low temperature anneal. Alternate preferred embodiments include more than three steps and incremental cooling.

Annealing method

Methods of doping Hg.sub.1-x Cd.sub.x Te (50) with fast diffusing dopants by immersion in a mercury reservoir (32) doped with the desired dopants are disclosed. Also, methods of core annihilation of Hg.sub.1-x Cd.sub.x Te slices or ingots by immersion in a heated mercury reservoir are disclosed. Preferred embodiments include dopants such as copper in a mercury reservoir (32) that is heated to 270.degree. C. for a Hg.sub.1-x Cd.sub.x Te slice, and a reservoir (32) that is heated to 150.degree. C. for a thin film of Hg.sub.1-x Cd.sub.xn Te on a CdTe substrate.

Core annihilation method of Hg.sub.1-x Cd.sub.x Te

The removal of residual impurities from semiconductor material is accomplished by solid state electromigration of the impurities from the semiconductor slice into a surrounding conductive liquid (e.g. Hg) which is maintained at a negative potential.

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Richardson, TX, United States of America

John H Tregilgas