National Institute of Advanced Industrial Science and Technology

Agency of Industrial Science and Technology

Japan Science and Technology Agency

Japan Science and Technology Corporation

Ministry of International Trade & Industry

Lockheed Missiles & Space Company, Inc.

Agency of Industrial Science and Technology Ministry of International

Irspec Corporation

Mutsuo Ogura

Takeyoshi Sugaya

Katsuhiko Nishida

Yasushi Nagamune

Shyh Wang

Hiroshi Hiroshima

Shigeo Okayama

Xue-Lun Wang

Nobuyuki Hayama

Kee-Youn Jang

Yoshinobu Sugiyama

Shing C Wang

Xuelun Wang

Wei Hsin

SungWoo Choi

Masanori Komuro

A hetero-junction bipolar phototransistor includes a photo-absorption layer formed of a first conductivity type semiconductor layer, and a collector operating as a barrier layer, a base layer, and an emitter layer, which are stacked in sequence on the photo-absorption layer. The photo-absorption layer, collector, base layer and emitter layer forms a first mesa structure, and an emitter contact layer forms a second mesa structure. The photo-absorption layer includes a semiconductor layer with a narrow gap corresponding to a light-sensing wavelength of the phototransistor. The collector includes a semiconductor layer with a wider gap than a gap of the photo-absorption layer. The base layer has an energy level equal to or higher than the energy level of the collector. The emitter layer has a wide gap as compared to the base layer, and an energy level in a valence band is lower than an energy level of the base layer.

Hetero-junction bipolar phototransistor with improved noise characteristic

A highly-efficient semiconductor light emitting diode with improved light extraction efficiency comprising at least a substrate having a plurality of crystal planes, a first conductivity-type barrier layer, an active layer serving as a light emitting layer and a second conductivity-type barrier layer stacked on the substrate. The semiconductor light emitting diode comprises a ridge structure configured from one flat surface and at least two inclining surfaces in the in-plane direction. The width (W) of the flat surface of the ridge structure is 2&#x3bb; (&#x3bb;: light emission wavelength) or less. The active layer is positioned in the laminating direction so that the shortest length (L) between two points is &#x3bb; (light emission wavelength) or less, wherewith the first point is the shortest point where the light emitted from the center (C) of the active layer begins total internal reflection at the interface between the inclining surfaces of the ridge structure and air, and the second point is a point where the flat surface begins.

Semiconductor light emitting diode

An array structure solves issues that exist in conventional compound semiconductor photodiode arrays, such as large cross talk, large surface leaks, large stray capacitance, narrow detection wavelength bands, and bad manufacturing yield, simultaneously. A photodiode array has, laminated upon a semiconductor substrate, a buffer layer () with a broad forbidden band width, an I-type (low concentration photosensitive layer () with a narrow forbidden band width, and an n-type semiconductor window layer () with a broad forbidden band width, wherein photodiode elements are electrically separated from adjacent elements, by doping the periphery of the p-type impurity, and the detection wavelength band is expanded, by making the n-type window layer () on the photosensitive layer () a thinner layer with crystal growth.

Compound semiconductor light-receiving element array

A highly sensitive and wide spectra-range mesa type photodetector having the impurity diffusion along the mesa-sidewall is provided. A mesa-type hetero-bipolar phototransistor or photodiode having a photo-absorption layer formed by a first semiconductor layer of a first conductivity type, an anode layer (or base layer) formed by a second semiconductor layer of a second conductivity type which has an opposite polarity with the first conductivity type, a wide band gap emitter or window layer formed by the third semiconductor layer on the anode layer, and the wide band gap buffer layer of the first conductivity type which has a relatively wide band gap semiconductor as compared with the second semiconductor layer on the substrate, which also serves as the cathode layer. And the first semiconductor layer, the second semiconductor layer and the wide band gap emitter or window layer is selectively etched to form the mesa structure. The diffusion region shaped like a ring in plan view is also provided from the exposed sidewall of this mesa structure toward the center of the device by a predetermined horizontal width, converted into the second conductivity type, which is the same conductivity type as the second semiconductor layer.

Photo transistor

This invention provides a photo-FET, in which a FET part and photodiode part are stacked, and the FET part and photodiode part are optimized independently in design and operational bias conditions. The semiconductor layer serving as a photo-absorption layer () is formed on the cathode semiconductor layer () of a photodiode part (). An electron barrier layer () with a wider bandgap semiconductor than a photo-absorption layer (), which also serves as an anode layer of a photodiode part (), is formed on a photo-absorption layer (). The channel layer () which constitutes the channel regions of the FET part is formed with a narrower bandgap semiconductor than an electron barrier layer () on an electron barrier layer (). The hole barrier layer () with a bandgap wider than the semiconductor which constitutes a channel layer () is formed on a channel layer (). The source electrode () and drain electrode () which are separated each others, are formed on a hole barrier layer (). The holes injected into the channel layer () by light illumination through the electron barrier layer () from the photo-absorption layer () are confined with the hole barrier layer (). And the electrons in a channel layer () are confined with the electron barrier layer () into the channel layer (), respectively.

Photo-field effect transistor and its production method

A photo-FET based on a compound semiconductor including a channel layer formed on a substrate constituting a current path between source and drain electrodes, serving as part of a photodiode and a photosensitive region. A back-gate layer that serving as a substrate-side depletion layer formation layer is disposed between the substrate and the channel layer, and applies to the channel layer a back-gate bias by photogenerated carriers upon illumination. A barrier layer is disposed on the front side of the channel layer that causes one of the photogenerated carriers to run through the channel layer and other of the photogenerated carriers to sojourn or be blocked off. A front-side depletion layer formation layer is disposed on the front side of the channel layer brings the front-side depletion layer into contact with the substrate-side depletion layer without illumination to close the current path in the channel layer, bringing the photo-FET to an off-state.

Photo-field effect transistor and integrated photodetector using the same

A quantum nanostructure semiconductor laser includes a strip-shaped ridge with a plurality of V-grooves formed on a compound semiconductor substrate in the direction of laser beam emission, with the V-grooves arrayed in parallel and with each V-groove extending orthogonally to the direction of laser beam emission. On the ridge, an optical waveguide is provided that includes a lower cladding layer, a plurality of quantum wires, and an upper cladding layer. The quantum wires are formed to a finite length corresponding to the stripe width of the laser beam, and are each located at a position corresponding to a V-groove location. The optical waveguide is trapezoidal in shape. The quantum wires do not project out beyond the width of the ridge, but the ends of the wires are converged and closed off with the upper and lower cladding layers toward higher index crystalline planes.

Quantum nanostructure semiconductor laser

On a grooved semiconductor substrate having a plurality of V-grooves individually extended in directions perpendicular to a direction Is of advance of an oscillated laser beam and mutually disposed in parallel along the direction Is of advance of the laser beam, a plurality of quantum wires () are formed on the V-grooves by selective growth of a Group III-V compound. The plurality of quantum wires are adapted to serve as limited-length active layer regions mutually disposed in parallel along the direction Is of advance of the laser beam with a period of an integer times of a quarter wavelength in a medium of a laser active layer and individually corresponding to stripe widths of laser. Consequently, a quantum nano-structure semiconductor laser satisfying at least one, or preferably both, of the decrease of a threshold and the stabilization of an oscillation frequency as compared with a conventional countertype can be provided.

Quantum nano-structure semiconductor laser

A negative resistance field-effect element that is a negative differential resistance field-effect element capable of achieving negative resistance at a low power supply voltage (low drain voltage) and also enabling securement of a high PVCR is formed on its InP substratehaving an asymmetrical V-groove whose surface on one side is a (100) plane and surface on the other side is a (011) plane with an InAlAs barrier layer () that has a trench (TR) one of whose opposed lateral faces is a (111) A plane and the other of which is a (331) B plane. An InGaAs quantum wire () that has a relatively narrow energy band gap is formed at the trench bottom surface as a high-mobility channel. An InAlAs modulation-doped layer () having a relatively wide energy band gap is formed on the quantum wire as a low-mobility channel. A source electrode () and a drain electrode () each in electrical continuity with the quantum wire () constituting the high-mobility channel through a contact layer () and extending in the longitudinal direction of the quantum wire () as spaced from each other, and a gate electrode () provided between the source electrode () and the drain electrode () to face the low-mobility channel () through an insulating layer or a Schottky junction, are provided. Owing to the foregoing configuration, a very narrow-width quantum wire whose lateral confinement size can, without restriction by the lithographic technology limit, be made 100 nm or less is usable as a high-mobility channel, whereby there can be obtained a negative resistance field-effect element that develops a negative characteristic at a low power supply voltage and enables securement of a high PVCR.

Negative resistance field-effect device

Quantum wire is formed on the bottom of a V-shaped groove in a V-grooved substrate as a channel between source and drain electrodes or as at least part of the channel. A photocarrier accumulation region is provided within the quantum wire or at a position connected to or adjacent to the quantum wire for accumulating charges generated when light shines onto a photosensitive region that comprises at least a clad layer that covers the quantum wire. A recess is provided in the upper clad layer to localize the photocarrier accumulation region. As a result, it is possible to provide a photodetector that exhibits high sensitivity, high speed and low power consumption in an expanded wavelength region. It is also possible to provide a photodetector capable of constructing core portions thereof by one-time selective growth.

Photodetector

A Group III atomic layer required for fabrication of a semiconductor quantum nanostructure is grown to be properly restricted to a monolayer. A substrate is configured to have a fast-growth surface portion where growth of a Ga atomic layer proceeds at a relatively high rate and a slow-growth surface portion where the growth of the Ga atomic layer proceeds at a relatively low rate. Ga atoms are supplied to the fast-growth surface portion in an amount not less than that which grows one layer of the Group III atoms. Excess Ga atoms on the fast-growth surface portion are allowed to migrate to the slow-growth surface portion by surface migration, thereby growing only one layer of the Ga atoms on the fast-growth surface portion.

Method for growing Group III atomic layer

A charged beam apparatus comprising a vacuum chamber having a moving mechanism inside and a sample chamber, the sample chamber being used placed in an ultra-high vacuum atmosphere or a gas atmosphere, wherein a flat surface is formed on that surface of the moving mechanism which faces the sample chamber, and a flange having a flat open surface is mounted between the vacuum chamber and the sample chamber such that the open surface is opposed to the flat surface with a tiny gap being formed between the open surface and the flat surface for permitting vacuum venting without imposing any restrictions on the moving mechanism, whereby the apparatus operates without restricting the action of the moving mechanism.

Charged beam apparatus

A surface-emitting semiconductor laser diode has a vertical multilayer active region and a lateral buried heterojunction. Effective carrier confinement to the active region is achieved, thereby permitting laser action at room temperature under continuous-wave operation with a low threshold current of about 2 mA.

Surface-emitting laser diode

A scanning-type lithographic and image-pickup device causes the terminal face of either a projecting optical fiber or a picking-up optical fiber to scan a given object in the plane of real image of an objective lens, projects a light through the projecting optical fiber onto the object, and receives the reflected light or a light of photoluminescence through the picking-up optical fiber. When this device is applied to a spectromicroscope, the quantitative surface information can be spectrally measured with high resolution and high reproducibility. When the device is applied to a contracting-projection exposure device or a selective laser annealing device, positional alignment and exposure pattern correction can be easily effected with high accuracy and high productivity. Simultaneous fabrication of a plurality of electronic components can be also obtained by use of this device.

Growing community of inventors

Tsukuba, Japan

Mutsuo Ogura