International Business Machines Corporation

Alan B Fowler

Allan Mark Hartstein

Jerry M Woodall

Praveen Chaudhari

Robert Rosenberg

Peter Daniel Kirchner

John Lawrence Freeouf

Hans S Rupprecht

Alan C Warren

Ralph Feder

Ned J Chou

William P Dumke

Gregory L Timp

James A VanVechten

A quantum well type signal translating device is constructed by providing an appendage in which a reflected wave can be employed to introduce constructive or destructive interference in electron wave conduction at the heterojunction.

Electron tuned quantum well device

A surface termination of a compound semiconductor is provided wherein conditions are provided for a pristine surface to be retained in an unpinned condition and a surface layer of a non-metallic material is provided. A GaAs substrate is heated in an oxygen-free atmosphere at high temperature with hydrogen sulfide, producing a pristine surface with a coating of gallium sulfide covered with a 1,000 nanometer covering of low temperature plasma enhanced chemical vapor deposited silicon dioxide.

Compound semiconductor surface termination

In a transistor structure a buried gate positioned in the layer above a conduction channel and below a broad gate which overlaps the source and drain, when the voltages applied to the buried gate and the overlapping gate are varied independently, a potential well between two barriers can be established which permits conduction by the physical mechanism of resonant transmission. The potential well between two barriers required for the resonant transmission mechanism is achieved in one structure by a buried gate under an overlapping gate with both width and separation dimension control and in a second structure using split-buried gate under an overlapping gate that is embossed in the region of the split gate. With gate and separation dimensions of the order of 1000 .ANG. switching speeds of the order of 10.sup.-12 seconds are achieved.

Voltage controlled resonant transmission semiconductor device

A process for defining small dimensions by forming a vertical step in an etchable material; edge depositing a masking material by angularly evaporating a metal; and etching away all of the first material not covered by the masking material; and device obtained by depositing source, drain, and gate defining material.

Method of making short channel IGFET

An interferometer is constructed by providing a bifurcated branch conductive path coplanar with a heterojunction in a semiconductor with a band discontinuity that produces a potential well so that electron wave conduction at the heterojunction can be locally influence with an electric field applied to one branch of the bifurcated path.

Semiconductor interferometer

The invention is a three-terminal transistor structure having five layers of materials that in combination provide conduction by high mobility carrier transport across the base in an energy valley above the conduction band. The conduction is by majority carrier tunneling injection from the emitter and transport at an upper valley level across the base. The resulting structure is capable of switching in times of 10.sup.-12 seconds.

Tunnel emitter upper valley transistor

A method for the fabrication of a gallium arsenide (GaAs) metal-semiconductor field effect transistor (MESFET) is described. The method requires the step of providing a semi-insulating GaAs substrate having thereon a layer of n doped GaAs and another layer of n+ doped Ga.sub.1-x Al.sub.x As, the latter being used as a diffusion source for n dopants in selectively doping the n GaAs layer underneath. The fabrication method further includes the step of employing highly directional reactive ion etching on silicon nitride to build insulating side walls thereby to effect the self-alignment of the gate of the MESFET with respect to its source and drain. GaAs MESFET fabricated using this method has its source and drain in close proximity having its gate therebetween. Utilizing the disclosed method, conventional photolithographic techniques can be employed to produce submicron self-aligned GaAs MESFETs.

Self-aligned process for fabricating gallium arsenide

A high aspect ratio collimating mask for use in ion beam epitaxy or ion implantation doping is formed through the use of damage-trail-forming materials which are irradiated through a mask and then etched. The high aspect ratio is obtained in part by the sequential formation of a plurality of spaced mask plates. The mask is useful in producing large scale integrated circuits by ion implantation during epitaxial growth of a crystal wafer.

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Yorktown Heights, NY, United States of America

Alan B Fowler