Massachusetts Institute of Technology

The Charles Stark Draper Laboratory, Inc.

Other

William D Goodhue

Wendell Eugene Rhine

William L Robbins

John S Haggerty

George B Kenney

Kirby B Nichols

Dennis D Rathman

R Allen Murphy

Julia Sigalovsky

Annamarie Lightfoot

Mark Alexander Hollis

Barry E Burke

Vinod M Menon

Joseph P Donnelly

Christine A Wang

Brian F Aull

Robert H Rediker

K Alexander McIntosh

Han Q Le

Erik K Duerr

Normand J Bergeron, Jr

Kurt Rauschenbach

Donald E Bossi

Robert J Bailey

Aram Karakashian

Lisa A Wright

L Ramdas Ram-Mohan

There is provided an avalanche photodiode array that includes a plurality of avalanche photodiodes. Each avalanche photodiode in the array includes a stack of active photodiode materials. The stack of active photodiode materials includes a first electrical contact layer, a second electrical contact layer; an absorber material layer and an avalanche material layer each disposed between the first electrical contact layer and the second electrical contact layer; and an optical interface surface to the avalanche photodiode. The optical interface surface consists of an exposed surface of the first electrical contact layer, arranged for incident external radiation to directly enter the first electrical contact layer. Each avalanche photodiode stack of active photodiode materials is laterally isolated from the other avalanche photodiodes in the photodiode array.

Photodiode array structure for cross talk suppression

A method passivates a surface of a semiconductor structure. The method provides III-V semiconductor material having a surface to be passivated. Upon the surface of the III-V semiconductor material to be passivated an oxide layer is formed. Thereafter, the surface of the III-V semiconductor material having the oxide layer is passivated, without desorption of the oxide layer and in a vacuum of 2&#xd7;10Torr, with a material having the ability to intermix with the oxide layer so as to exchange oxygen, passivation layer material, and III-V semiconductor material therebetween to form graded layers of oxidized III-V and passivation material.

Method of fabrication for III-V semiconductor surface passivation

The present invention is directed to the development of compact, coherent sources emitting in the terahertz frequency region using interface phonons. In accordance with a preferred embodiment, a semiconductor heterostructure light emitting device includes a quantum cascade structure having at least an upper lasing level and a lower lasing level. The system uses heterostructure interface phonon bands to depopulate the lower lasing level of at least a three level semiconductor device. The device includes multiple coupled quantum well modules. In alternate preferred embodiments, the device includes quantum dot layers and/or, quantum wire structures, and/or mini-bands in a superlattice, for example, GaAs/AlGaAs superlattice. The phonons in the device improve efficiency, decrease the threshold current and result in system temperatures that are as high as room temperature. The semiconductor device provides emission of terahertz radiation. In a preferred embodiment the semiconductor device provides at least one emission in the terahertz radiation region and in a far infrared region of the electromagnetic spectrum. The emissions include a first emission having a first energy level and a second emission having a second energy level.

Systems and methods using phonon mediated intersubband laser

An electronic device package is provided, consisting of reaction bonded silicon nitride structural and dielectric components and conductor, resistor, and capacitor elements positioned with the package structural components. The package consists of a ceramic package base characterized by a dielectric constant less than 6, of reaction bonded silicon nitride, or a heat spreader material. An electrical conductor is positioned on, embedded in, or attached to the package base for making electrical contact to an electronic device supported on the base and in preferred embodiments, a resistor is attached to the package base. The invention also provides package sidewalls connected to the package base, preferably of reaction bonded silicon nitride, and at least one electrical conductor extending to an outside surface of the package sidewalls for making electrical contact to an electronic device supported by the package base. The reaction formed electronic device packages of the invention provide the ability to support high device signal frequencies, high device operational temperatures, and high environmental temperatures, due to the characteristics of the package materials. The reaction formed electronic device packages of the invention may be produced with a nitriding process during which the overall package structure exhibits minimal shrinkage. As a result, the reaction formed electronic device packages of the invention may be shaped to finished dimensions before the nitriding process with complicated and tight-tolerance geometries of package structural, conducting, resistive, and capacitive components.

Net-shape ceramic processing for electronic devices and packages

A method of producing electronic device packages is provided, consisting of the steps of shaping a package preform and heating the package preform in a nitrogen-containing atmoshpere to nitride the package preform. The shaped package preform may consist of package base, sidewall, conductor, resistor, or capacitor components. The package base and sidewall components may be formed of silicon powder. The method also accommodates the step of inserting a semiconducting material into the package preform and heating the semiconducting material component along with the package preform. The inserted semiconducting material component may be processed to define active electronic device areas on the component either before or after the step of heating the shaped package preform and inserted semiconducting material component. The package production methods of the invention provide the ability to produce reaction bonded structural and dielectric package components by way of a nitriding process that causes minimal overall shrinkage of the package. As a result, reaction formed electronic device packages of the invention may be shaped to finished dimensions before the nitriding process with complicated and tight-tolerance geometries of package structural, conducting, resistive, and capacitive components. The package production methods of the invention also provide the ability to interleave electronic device and packaging manufacturing sequence steps, resulting in increased manufacturing efficiency, as well as improved performance in the devices and packages produced. Device substrates or partially fabricated devices may be embedded into semi-finished packages, whereby completion of device fabrication coincides with completion of package fabrication. This makes possible the fabrication of active devices and circuits in a fully packaged environment.

This invention provides an optical converter suitable for use as the gain medium in lasers, optical amplifiers and other optical devices. The converter consists of at least one and preferable two or more optical converter elements which are sandwiched and separated by inactive dielectric layers. An optical pump beam may be passed to the active converter elements through an anti-reflection layer at one surface of the converter and a high reflection mirror may be provided at the opposite side of the converter to reflect the pump beam incident thereon back into the converter for a second pass. Each converter element has one or more absorber layers, at least one radiation layer receiving energy from the absorber layers and preferably outputting energy at a slightly different wavelength than the wavelength at which the absorber layers optimally absorb, and preferably at least one index-of-refraction compensator (IRC) layer which compensates for changes in index-of-refraction induced by the absorber and radiator layers to provide a low divergence far field optical intensity profile for the converter with no substantial side lobes.

Solid state optical converter

An electro-optical device comprising a CCD structure having charge wells, the charges therein being controlled by a modulating signal applied to said CCD structure. A multiple quantum well structure having quantum well regions associated with the charge wells of said CCD structure, the charges in the CCD charge wells determining the value of the electric fields at said quantum well regions and, hence, the electro-absorption effects at said quantum well regions. The intensity of an input electromagnetic wave signal directed through said electro-optical device is thereby spatially modulated by the electro-absorption effects at the quantum well regions of the multiple quantum well structure. A novel CCD structure using quantum well regions to form the charge wells thereof can be used as the CCD structure for controlling the electric fields at the multiple quantum well structure.

Spatial light modulator using charge coupled device with quantum wells

A method and apparatus for forming tapered thickness and material content of III-V material, or alloys thereof, in particular GaAs and AlGaAs, by gradient thermal heating of substrates during epitaxial growth and the optoelectronic structures formed thereby.

Method for forming tapered laser or waveguide optoelectronic structures

An improved two-dimensional semiconductor surface-emitting laser array is described in which two intra-cavity internal reflecting surfaces are formed at a 45.degree. angle to the plane of the active layer of the semiconductor laser so as to internally reflect light from each end of the active layer in a direction normal to the plane of the active layer with a buried reflective mirror provided in the path of one of said reflections, so as to transmit reflected light back through the laser and out the top surface of the array.

Two-dimensional surface-emitting laser array

Tapered laser or waveguide optoelectronic method

An electro-optical device for providing spatial modulation of an incoming electromagnetic wave signal, and preferably a two-dimensional incoming signal applied orthogonally to an input plane of the device, which device includes an array of modulation regions for providing such modulation of portions of the incoming signal. An array of first reflective mirrors are positioned so as to direct the incoming electromagnetic wave signal portions through the interaction layer regions of the modulation regions in a direction substantially parallel thereto and an array of second reflective mirrors directs the modulated electromagnetic wave signal portions outwardly from the device to provide a two-dimensional spatially modulated output electromagnetic wave signal.

Spatial light modulator

Horizontal and vertical transistors, such as, HEMT/SDHT devices are described with opposed gates for preventing substrate leakage current along with the methods for making same. Also a process for making single gate angled V-HEMT devices is described.

Growing community of inventors

Chelmsford, MA, United States of America

William D Goodhue