International Business Machines Corporation

US Government As Represented by the Secretary of the Army

Leo Esaki

Leroy L Chang

Chin-An Chang

George A Sai-Halasz

Emilio E Mendez

Hideo Ohno

Raphael Tsu

Hiro Munekata

Stephan vonMolnar

Wen-I Wang

A new semiconductor material or compound and method for its manufacture is disclosed. The material or compound has the Formula III-V or IV which includes as part of the compound, a transition element or a rare earth element present in an amount sufficient to change the material or compound from a paramagnetic state to a locally ordered magnetic state. The material or compound is made by depositing III, and V or IV and a transition element or a rare earth element onto a substrate at conditions such that the transition element or rare earth element that is deposited on the substrate is not in equilibrium with the material or compound. By employing this technique new semiconductor materials or compounds can be made including Ga.sub.1-x Mn.sub.x As and In.sub.1-x Mn As where Mn is present in an amount greater than about 5.4.times.10.sup.20 cm.sup.-3.

Class of magnetic materials for solid state devices

A new semiconductor material or compound and method for its manufacture is disclosed. The material or compound has the Formula III-V or IV which includes as part of the compound, a transition element or a rare earth element present in an amount sufficient to change the material or compound from a paramagnetic state to a locally ordered magnetic state. The material or compound is made by depositing III, and V or IV and a transition element or a rare earth element onto a substrate at conditions such that the transition element or rare earth element that is deposited on the substrate is not in equilibrium with the material or compound. By employing this technique new semiconductor materials or compounds can be made including Ga.sub.1-x Mn.sub.x As and In.sub.1-x Mn.sub.x As where Mn is present in an amount greater than about 5.4.times.10.sup.20 cm.sup.-3.

The present invention is directed to novel optoelectronic devices, such as light emitters and detectors, that have a unique combination of semiconductor materials that provides a band arrangement resulting in improved efficiency of carrier injection. The devices are quantum well type devices in which discrete electronic states are formed by size quantization effects in the quantum well region. Electromagnetic radiation of emission and absorption occurs by the transition of electrons from a first energy state to a second energy state in either the conduction band or the valence band of the quantum well layer. The bands edges of the layers are offset such that under an appropriate bias, the discrete energy states reside in the bandgap of one of the electrodes and in an allowed region of the other electrode, with one state residing in the conduction band of one electrode and the other state residing in the valence band of the other electrode. The wavelength of the emitted or detected light is inversely proportional to the energy difference between the first and second states. Wavelength customization is facilitated by techniques for adjusting the energy difference.

Optoelectronic devices based on intraband transitions in combinations of

The mobility of carriers in the channel region of a field effect transistor can be increased by providing a layered structure wherein electrons are separated from impurities. The channel is made up of external layers of wide bandgap material and internal layers with a narrower bandgap where the bottom of the conduction band of one layer is below the top of the valence band of the adjacent layer. A structure is shown with a layered channel having AlSb external layers and at least one or both of InAs and GaSb internal layers.

Field effect transistor

A semiconductor superlattice is provided with a one-dimensional quantum pipeline type carrier path. The pipeline is formed at the intersection of different energy level layers of the superlattice. Conductivity modulation through an adjacent exposed surface is employed for control in the pipeline and in arrays thereof. The pipeline carrier path involves both electrons and holes. A structure of Ga.sub.1-x Al.sub.x As with alternating 100.ANG. and 500.ANG. thick layers of different x has positioned, intersecting those layers, a 100.ANG. thick GaAs layer covered by a GaAlAs layer. Control and contacting electrodes are positioned on the exposed surfaces.

One-dimensional quantum pipeline type carrier path semiconductor devices

A field-effect transistor includes a conduction channel between a source terminal and a drain terminal, which channel employs holes as the charge carriers. The conduction channel is disposed within a layer of material comprising a group III-V compound of the periodic table and having a crystalline lattice structure which is stressed in two dimensions by means of epitaxial growth upon a thicker and rigid supporting layer comprising a different group III-V compound having a larger lattice spacing. The layer having the conduction channel is relatively thin being on the order of a few electron wavelength in thickness. The stretching of the layer having the conduction channel shift the energy levels of holes therein to remove the degenerate state thereof, thereby elevating light holes to an energy level characterized by increased mobility.

Semiconductor device with hole conduction via strained lattice

Misfit dislocation density at an InAs-GaAs interface is reduced in both InAs-GaSb and In.sub.1-x Ga.sub.x As-GaSb.sub.1-y As.sub.y superlattices grown on GaAs substrates by means of an MBE (molecular beam epitaxy) growth technique consisting of a step graded sequence of composition layers between substrate and superlattice whose composition changes in discrete concentration steps from the composition of the substrate to the composition of the superlattice.

MBE Growth technique for matching superlattices grown on GaAs substrates

FET With heterojunction induced channel

Misfit dislocation density at an InAs-GaAs interface is reduced in both I-GaSb and In.sub.1-x Ga.sub.x As-GaSb.sub.1-y As.sub.y superlattices grown on GaAs substrates by means of a MBE (molecular beam epitaxy) growth technique consisting of a step graded sequence of composition layers between substrate and superlattice whose composition changes in discrete concentration steps from the composition of the substrate to the composition of the superlattice.

MBE growth technique for matching superlattices grown on GaAs substrates

A heterojunction transistor device having emitter and collector regions of a first conductivity type separated by an ultra-thin base region of a second conductivity type. Abrupt heterojunctions are formed which are then heat treated to allow the formation of graded heterojunctions exhibiting rectifying characteristics. Typically, the emitter and collector regions are comprised of GaSb while said base region is comprised of InAs. The band gap of the emitter region is selectively chosen to be relatively wide in comparison to the band gap of the base region. Moreover, the band gap of the emitter and collector regions is substantially equal to the conduction band discontinuity between the emitter and base, and the band gap of the base is substantially equal to the valance band discontinuity and the edge of the conduction band of the base region is substantially coincident with the edge of the valance band of the emitter region. The base region is heavily doped to reduce the base resistance thereby maintaining an injection efficiency close to unity.

Heterojunction transistor

Disclosed is a tunnel diode consisting of an accumulation region of p-type GaSb and an accumulation region of n-type InAs separated by a thin layer of a quaternary compound consisting of InGaSbAs. Such a diode structure converts the interface between the two accumulation regions of p-type and n-type material from what would normally be an ohmic junction into a tunneling junction. Such a tunnel diode requires no heavy doping which is normally required for a tunnel diode.

InAs-GaSb Tunnel diode

A detector and/or mixer of electromagnetic energy in the microwave-infrared region of the electromagnetic spectrum comprised of a body of semiconductor material having a superlattice region consisting of, for example, InAs - GaSb wherein the thickness of alternating epitaxial planar layers is in the range of 30A to 80A. Incident radiation perpendicular to the planar regions results in an electric field being provided in the plane of the layers which causes a reduction in the superlattice bandwidth and accordingly an increase in the transverse effective mass of the carriers. This results in a decrease in the perpendicular conductivity through the superlattice region.

Microwave-infrared detector with semiconductor superlattice region

A superlattice structure is disclosed in which alternating layers of semiductor alloy materials provide a one dimensional spatial periodic variation in band edge energy. A first layer of the superlattice device is an alloy including a first Group III material and a first Group V material, preferably In As, while the second layer is an alloy including a second Group III material different from the first Group III material and a second Group V material different from the first Group V material, and preferably GaSb. In the superlattice structure the valence band of the second alloy is closer to the conduction band of the first alloy than it is to the valence band of the first alloy.

Heterojunction superlattice with potential well depth greater than half

A system and method including the use of hydrogen in the molecular beam evaporation process for epitaxy growth, such as in the formation of GaAs and GaAlAs and Sn for n-type dopant impurity. In a molecular beam epitaxy system, a hydrogen beam introduced and, along with the molecular beam, is directed on the substrate during the epitaxy growth such that the presence of the relatively small volume of hydrogen influences the physical surface properties of the epitaxially grown material and therefore the quality of the epitaxy.

Molecular-beam epitaxy system and method including hydrogen treatment

A heterojunction structure made of two semiconductor layers is disclosed in hich light is applied to the structure and absorbed, and the emission of light from the structure is controlled by an electric field applied perpendicularly to the planes of the layers. It is further disclosed that the device can be employed as a selective light filter or modulator.

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Chappaqua, NY, United States of America

Leo Esaki