International Business Machines Corporation

William H Price

Sampath Purushothaman

Masanori Murakami

Jerry M Woodall

Steven Lorenz Wright

Hormazdyar M Dalal

Sandip Tiwari

Harsaran S Bhatia

Thomas N Jackson

Daniel C Edelstein

Vincent James McGahay

Eric D Perfecto

George E White

Suryanarayana Kaja

Henry Atkinson Nye, Iii

Umar M Ahmad

Srinivasa N Reddy

Vivek M Sura

Satya P Bhatia

Satya Pal Singh Bhatia

Umar Moez Uddin Ahmad

Brian George Ottey

A corrosion resistant, multi-layer structure on a substrate including an adhesion metallic layer on the substrate, a cushion metallic layer on the adhesion layer, a diffusion barrier layer on the cushion layer, and an impermeable gold layer that encapsulates all the layers, is substantially even on all sides of the layers, and contacts a region on the substrate adjacent the layers to prevent oxidation and corrosion.

Corrosion-free multi-layer conductor

A structure comprising a layer of copper, a barrier layer, a layer of AlCu, and a pad-limiting layer, wherein the layer of AlCu and barrier layer are interposed between the layer of copper and pad-limiting layer.

Robust interconnect structure

A ceramic substrate pad used for establishing brazed connection between a pin and the substrate in the packaging of microelectronic semiconductor circuit chip. The pad is characterized by a stepped setback in the upper surface thereof which setback is oxidized to prevent wetting by the brazing alloy which bonds the pin to the pad. Stresses attributable to the brazing are isolated from the setback area and thus have reduced effect in causing cracking at the edges of the pad-substrate interface.

Module input-output pad having stepped set-back

A thin-layer metallization structure in which the final gold layer is deposited by evaporation with the surface onto which it is evaporated maintained at an elevated temperature. By evaporating the uppermost gold layer of the structure at an elevated substrate temperature, the gold atoms have a higher mobility, causing the deposited gold to spread over the edge of the structure and cover the otherwise exposed edges, including the edge at the copper interface.

Process for corrosion free multi-layer metal conductors

The control of barriers to carrier flow in a contact between a metal and a higher band gap semiconductor employing an intermediate lower band gap semiconductor with doping and greater than 1.5% lattice mismatch. A WSi metal contact of doped InAs on GaAs of 7.times.10.sup.-6 ohm/cm.sup.2 is provided.

Method for forming distributed barrier compound semiconductor contacts

In a semiconductor device, a contact with low resistance to a III-V compound semiconductor substrate was fabricated using refractory materials and small amounts of indium as the contact material. The contact material was formed by depositing Mo, Ge and W with small amounts of In onto doped GaAs wafers. The contact resistance less than 1.0 ohm millimeter was obtained after annealing at 800.degree. C. and the resistance did not increase after subsequent prolonged annealing at 400.degree. C.

Thermally stable low resistance contact

A thermally stable low resistance ohmic contact to gallium arsenide is fabricated using a layer of refractory material, and a layer of indium and a metal which forms thermally stable intermetallic compounds or single solid phase with indium. In forming the contact, a layer of indium is sandwiched between two layers of nickel, the sandwiched array of layers sitting on the substrate with the refractory tungsten layer on top to form a stratified structure. The stratified structure is heated to form nickel and indium intermetallic compounds and InGaAs layer at the metal/semiconductor interface. A thin layer of nickel between the indium and the gallium arsenide tends to form intermetallic compounds and limit a rate of diffusion of the indium into the gallium arsenide during heating so as to form a uniform fine distribution of InGaAs layer at the metal/gallium arsenide interface which results in low contact resistance. A contact resistance of 0.3 ohm-millimeters is obtained at elevated temperature in the range of 700.degree.-1200.degree. C. The resistance is stable after annealing at 400.degree. C. for 100 hours.

Thermally stable ohmic contact for gallium-arsenide

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William H Price