Northrop Corporation

Northrop Grumman Systems Corporation

John W Tully

Mark David Brown

James M Rowe

Paul Kraatz

William Hant

Benedict B O'Brien

V Warren Biricik

Rudolph W Modster

King L Hu

David Arthur Luippold

Richard F Sorensen

Wesley J Thompson

Don L McCoy

Vahram W Biricik

George V Case

Susan LaColla Wade

A highly conductive thermoplastic elastomer gap filler having superior durability and EMI shielding properties. According to the preferred embodiment, the TPE comprises graphite fiber having a nickel-copper-nickel coating formed thereabout that is suspended within an elastomer, which preferably comprises polyvinylchloride. The TPE of the present invention is particularly well-suited for reducing radio frequency electromagnetic radiation reflected by gaps formed between adjacent panels of a structure, and is particularly well-suited for the maintenance and repair of low observable aircraft. The TPE of the present invention may further be modified to include carbon black filler.

Highly conductive thermoplastic elastomer (TPE) gap filler

A hot-melt fastener filler placeable within a void atop an in-place fastener countersunk within a surface such as an exposed aircraft surface. The filler includes an electrically-conductive mat fabricated of at least one ply having a plurality of non-woven electrically conductive fibers each having a core strand coated with a nickel layer, preferably coated with two additional layers of copper and nickel, and generally uniformly dispersed within a thermoplastic elastomer. Electrically conductive carbon black particulate can be distributed throughout the elastomer, and the mat preferably is fabricated of two plies oriented at 0&deg; and 90&deg; to each other. A pressure sensitive adhesive can be provided on one side of the sheet to thereby permit secured placement prior to completion of installation. The fastener filler allows not only regularly scheduled maintenance, but also permits quick and generally uncomplicated field-level repairs for assuring equipment availability at remote sites.

Hot melt fastener filler

Highly conductive elastomeric sheet. Preferably, the conductive elastomeric sheet comprises a conductive wire mesh loaded into an elastomeric matrix from which is also loaded with a conductive particulate. Preferably, the particulate comprises carbon particulate having a sub-micron size, and is present in an amount between ten percent (10%) to twenty percent (20%) by volume. The conductive elastomeric materials are exceptionally durable and retain a high degree of conductivity well-after ten thousand (10,000) fatigue performance cycles.

Highly conductive elastomeric sheet

A highly conductive thermoplastic elastomer (TPE) gap filler having superior durability and EMI shielding properties. According to the preferred embodiment, the TPE comprises graphite fiber having a nickel-copper-nickel coating formed thereabout that is suspended within an elastomer, which preferably comprises polyvinylchloride (PVC). The TPE of the present invention is particularly well-suited for reducing radio frequency electromagnetic radiation reflected by gaps formed between adjacent panels of a structure, and is particularly well-suited for the maintenance and repair of LO aircraft. The TPE of the present invention may further be modified to include carbon black filler.

Method for reducing reflected radio frequency electromagnetic radiation

A semiconductor window which is transparent to light in the infrared range and which has good electrical conductivity is formed of a prefabricated semiconductor sheet bonded to a substrate material by optical contact. The sheet is a substantially uniformly doped wafer sufficiently thin that inherent absorption bands do not affect transmission. The sheet is contact bonded to the surface of an undoped transparent substrate without diffusion, growth or deposition on the surface. Windows having particular optical band pass characteristics are formed utilizing a zinc selenide substrate and a gallium arsenide sheet.

Optically transparent, electrically conductive semiconductor windows

Methods are disclosed for making semiconductor windows which are transparent to light in the infrared range which have good electrical conductivity and are formed of a substrate material (11) having a semiconductor coating (14) having a dopant included therein. The coating is diffused, grown or deposited on one surface of the substrate and is controlled to obtain both low electrical resistivity and high infrared transmissivity. The coating can be formed of the same material as the substrate or can be a different material. Windows having particular thermal properties are formed utilizing zinc selenide and zinc sulfide as the substrate.

Method of manufacture of optically transparent electrically conductive

A process for forming refractory metal ohmic contacts comprises masking a group III-V semiconductor substrate and opening windows thereon. Metal ions are implanted through the window to a sufficient concentration to connect to electronic features in the substrate. Following implantation, a refractory metal ohmic contact is deposited in the same windows and is passivated. Next, the implanted ions are activated by annealing so the refractory metal ohmic contacts are electrically connected to the electrical features in the substrate.

Refractory metal ohmic contacts and method

A bipolar transistor is constructed to include a substrate, a collector layer epitaxial grown on the substrate and a base layer ion implanted in the collector layer. Next a further epitaxial layer is grown on the collector layer over the ion implanted base layer. A base contact region is ion implanted in this further epitaxial layer between the surface of this further layer and the base layer. The base contact region surrounds and defines an emitter in the further layer. A base ohmic contact is formed on the surface of the further layer in a location overlaying and contacting the base contact region. An emitter ohmic contact is also formed on the surface of the further layer in contact with the emitter. Additionally a collector ohmic contact is also formed on this same surface in a position isolated from the emitter by the base contact region. The collector ohmic makes an electrical contact with the collector by utilizing the further layer as a contact pathway.

Planar bipolar transistors including heterojunction transistors

A semiconductor window which is transparent to light in the infrared range and which has good electrical conductivity is formed of a substrate material having a semiconductor coating having a dopant included therein. The coating is diffused, grown or deposited on one surface of the substrate and is controlled to obtain both low electrical resistivity and high infrared transmissivity. The coating can be formed of the same material as the substrate or can be a different material. Windows having particular thermal properties are formed utilizing zinc selenide and zinc sulfide as the substrate.

Optically transparent electrically conductive semiconductor windows

Planar bipolar transistors including heterojunction transistors and

An aluminum liftoff masking process is effected on a prepared gallium arsenide wafer having a base thereon. Successive layers of silicon dioxide and aluminum are deposited on the wafer. The aluminum and silicon dioxide layers are successively etched, including undercutting of the aluminum layer. Base majority carriers are implanted through the windows to the base and refractory metal ohmic contacts are built up in the windows. After forming the base contacts, the base contact areas may be passivated. The aluminum layer and any overlaying layers thereon are removed by etching off the aluminum.

Aluminum liftoff masking process and product

A semiconductor window which is transparent to light in the infrared range and which has good electrical conductivity is formed with a substrate of semi-conductor material which has a conduction modifying dopant diffused, grown or deposited on one surface thereof to a substantial depth so that a layer thereof exhibits reduced resistance to a value below 10 ohms/square. Anti-reflection dielectric layers are stacked on both outer surfaces thereof. The dielectric substrate may be of silicon, germanium or gallium arsenide depending on the transparency bandwidth of interest. The thickness of the substrate and the doping of the surface thereof is closely controlled to obtain both low electrical resistivity and high optical transmissivity.

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Rolling Hills Estates, CA, United States of America

John W Tully