Sony Corporation

Tdk-lambda Corporation

The University of Electro-communications

Tdk-lameda Corporation

Kabushiki Kaisha Campuscreate

Kazushi Nakano

Akira Ishibashi

Hiroyuki Okuyama

Satoshi Ito

Junichi Sato

Toshio Fujino

Masakazu Ukita

Tomonori Hino

Akio Machida

Dharam Pal Gosain

Shigetaka Tomiya

Eiji Takegami

Eisaku Kato

Katsuhiro Akimoto

Kazushi Watanabe

Satoshi Tomioka

Kouji Higuchi

Tatsuyoshi Kajikawa

Hiroshi Yoshida

Masao Ikeda

Masaharu Nagai

Satoshi Taniguchi

Etsuo Morita

Michinori Shiomi

Satoru Kijima

Satoshi Matsumoto

Masashi Shiraishi

Sakurako Okamoto

Yukihisa Hitsuda

Atsushi Toda

Takashi Kobayashi

Kenji Kondo

Norikazu Nakayama

Takao Miyajima

Masafumi Ozawa

Toyoharu Ohata

Futoshi Hiei

Hiroyasu Noguchi

Reiko Takeishi

Yuko Morinaga

Rikako Minatoya

There is provided a digital controller which can reduce a variation in output voltage as compared to the conventional digital controller at the time of abrupt changes in load and in input of a power amplifier. The digital controller is built in the power amplifier for supplying an output voltage vto a load and is equipped with a manipulated variable calculating unit which detects the output voltage vto calculate a manipulated variable &#x3be;and a signal generating unit which converts the manipulated variable &#x3be;into a signal for making the power amplifier operate. A feedforward function from an equivalent disturbance qy caused by the variation in the load is replaced by a feedback function from the output voltage vand the manipulated variable &#x3be;, thereby allowing a transfer characteristic from the disturbance qy to the output voltage vto result in a quadratic differential characteristic. Consequently, the variation in output voltage can be reduced as compared to the conventional controller at the time of the abrupt changes in the load and in the input of the power amplifier.

Digital controller for controlling output voltage under large variations in load and supply voltage

There is provided a digital controller which can generate no oscillation even if sensing a load side and enables control of supplying a desired voltage to the load. In an power amplifier which supplies an output voltage vto the load connected via a load connecting line, a load voltage vand the output voltage vare periodically sampled to calculate a manipulating variable &#x3be;from the output voltage v, the load voltage vand an arbitrary target value r. Based on the manipulating variable &#x3be;calculated, a control signal is output to the power amplifier. As a result, when connecting an LC filter with a load deviceof the power amplifier intended for a control target and besides the load connecting line is long, a robust digital controller without generating oscillation even if sensing the load side is performed can be realized.

Digital controller

A robust digital controller is equipped with a high degree of approximation and is able to incorporate a novel two-degree-of-freedom robust digital control system without substantially considering the magnitude of the control inputs and there is provided its designing device. A control compensating means is configured as an integral type control system in which a discrete transfer function W(z) between a target value r and a controlled variable y is approximated to a higher-approximate quadratic approximate model transfer function W(z) and an arithmetic processing can be performed within the digital controller based on the model transfer function W(z). Further, the designing device automatically calculates parameters constituting the control system. Consequently, a robust digital controller can be easily realized that is equipped with a high degree of approximation as compared with a conventional approximate digital control system for realizing a first-order model and is robust against output noises.

Robust digital controller and its designing device

Disclosed are a method of producing a crystalline semiconductor material capable of improving the crystallinity and a method of fabricating a semiconductor device using the crystalline semiconductor material. An amorphous film is uniformly irradiated with a pulse laser beam (energy beam) emitted from an XeCl excimer laser by 150 times so as to heat the amorphous film at such a temperature as to partially melt crystal grains having the {100} orientations with respect to the vertical direction of a substrate and melt amorphous film or crystal grains having face orientations other than the {100} orientations. Silicon crystals having the {100} orientations newly occur between a silicon oxide film and liquid-phase silicon and are bonded to each other at random, to newly form crystal grains having the {100} orientations. Such a crystal grain creation step is repeated, to form a crystalline film which has crystal grains preferentially grown in the {100} orientations with respect to the vertical direction of the substrate and thereby has sharp square-shaped crystal grain boundaries.

Method of producing crystalline semiconductor material and method of fabricating semiconductor device

A manufacturing method for a crystalline semiconductor material including a plurality of semiconductor crystal grains is provided. The manufacturing method includes forming an amorphous or polycrystalline semiconductor layer on a substrate having a flat surface; forming a plurality of projections each having a side wall surface substantially perpendicular to the flat surface of the substrate, a height set in the range of about 1 nm to less than or equal to about &#xbc; of the thickness of the semiconductor layer, and a lateral dimension set in the range of about 3 &#x3bc;m to about 18 &#x3bc;m in a direction parallel to the flat surface of the substrate; and heating the semiconductor layer a number of times by using a pulsed laser thereby forming the crystalline semiconductor material including the crystal grains each having a specific plane orientation with respect to a direction perpendicular to the flat surface of the substrate so that the crystal grains respectively correspond to the projections. Accordingly, the position, size, and plane orientation of a crystal can be controlled by a simple step, and a crystalline semiconductor material excellent in planarity as a film can be formed.

Manufacturing method for crystalline semiconductor material and manufacturing method for semiconductor device

Method for manufacturing an oriented crystalline semiconductor using a pulsed laser

A luminescent semiconductor device comprises: an active layer composed of a Group II-VI semiconductor device which comprises at least one Group II element selected from the group consisting of zinc, magnesium, beryllium, cadmium, manganese and mercury, and at least one Group VI element selected from the group consisting of oxygen, sulfur, selenium and tellurium. the Group II-VI compound semiconductor forming said active layer contains at least one element selected from the group consisting of magnesium, beryllium and cadmium as the Group II element and tellurium as the Group VI element. At least one antidiffusion layer preventing diffusion of these elements from the active layer is provided on at least one surface of the active layer.

Luminescent semiconductor device with antidiffusion layer on active

A semiconductor light emitting device comprises: a compound semiconductor substrate; an n-type cladding layer on the compound semiconductor substrate; an active layer on the n-type cladding layer; a p-type cladding layer on the active layer: and a p-type contact layer on the p-type cladding layer, the n-type cladding layer, the active layer, the p-type cladding layer and the p-type contact layer being made of II-VI compound semiconductors containing at least one of group II elements selected from the group consisting of Zn, Cd, Mg, Hg and Be and at least one of group VI elements selected from the group consisting of S, Se, Te and O, characterized in that at least the active layer has undulations and at least the p-type layer is flat. A method for manufacturing a semiconductor light emitting device having: a compound semiconductor substrate; an n-type cladding layer on the compound semiconductor substrate; an active layer on the n-type cladding layer; and a p-type cladding layer on the active layer, the n-type cladding layer, the active layer and the p-type cladding layer being made of II-VI compound semiconductors containing at least one of group II elements selected from the group consisting of Zn, Cd, Mg, Hg and Be and at least one of group VI elements selected from the group consisting of S, Se, Te and O, characterized in that the n-type cladding layer, the active layer and said p-type cladding layer are grown by varying, for the respective layers, the ratio of the molecular beam intensity of the group VI element relative to the molecular beam intensity of the group II element.

Semiconductor light emitting device, its manufacturing method and

The semiconductor light emitting device includes a semiconductor substrate (1), a first conductivity type first cladding layer (2) deposited on the semiconductor substrate (1), an active layer (4) deposited on the first cladding layer (2), and the second conductivity type second cladding layer (6) deposited on the active layer (4). The first and the second cladding layers (2, 6) are made of the II/VI-compound semiconductors including at least one kind of II group elements such as Zn, Hg, Cd, Mg and at least one kind of VI group elements such as S, Se, Te. The lattice mismatching .DELTA.a/a (%) between at least one of the first cladding layer (2) and the second cladding layer (6) and the substrate is set within the range of -0.9%.ltoreq..DELTA.a/a.ltoreq.0.5% (reference symbols a and a.sub.c represent the lattice constant of the semiconductor substrate and the lattice constant of at least either of the first and second cladding layers, and .DELTA.a is obtained from .DELTA.a=a.sub.c -a).

Method of fabricating of light emitting device with controlled lattice

A semiconductor light emitting device ccomprises a first cladding layer, an active layer and a second cladding layer which are stacked on a semiconductor substrate. At least a part of the first cladding layer and the second cladding layer has a superlattice structure comprising II-VI compound semiconductor. Another semiconductor light emitting device comprises a first cladding layer, a first guide layer, an active layer, a second guide layer and a second cladding layer which are stacked on a semiconductor substrate. At least a part of the first cladding layer, the first guide layer, the second cladding layer and the second guide layer has a superlattice structure. Still anothr semiconductor light emitting device comprises a defect decomposing layer, a defect blocking layer, a first cladding layer, an active layer, a second cladding layer which are stacked on a semiconductor substrate. The defect decomposing layer and the defect blocking layer comprise a superlattice structure.

Semiconductor light emitting device with a Mg superlattice structure

An epitaxial growth method of semiconductor can reliably avoid irregularities from being produced when a II-VI compound semiconductor is grown epitaxially. When this method is applied to a method of manufacturing a semiconductor light-emitting device, it is possible to obtain a semiconductor light-emitting device having a long life and excellent light-emitting characteristic. When a II-VI compound semiconductor is grown epitaxially, a VI/II ratio, i.e., a supplying ratio of VI-group element and II-group element used in the epitaxial growth is selected in a range of from 1.3 to 2.5.

Epitaxial growth method of semiconductor

A II-VI group compound semiconductor light-emitting device can emit light of a short wavelength at room temperature. Operation characteristics, such as current--voltage characteristics and current--light output characteristics can be stabilized and a life of this semiconductor light-emitting device can be extended. The semiconductor light-emitting device comprises a substrate (1), at least a first cladding layer (2) of a first conductivity type, an active layer (3) and a second cladding layer (4) of a second conductivity type, wherein at least the active layer (3) is made of a II-VI group compound semiconductor and the active layer (3) is doped by either or both of n-type and p-type dopants.

Semiconductor light-emitting device

A semiconductor light emitting device comprises a first cladding layer, an active layer and a second cladding layer which are stacked on a semiconductor substrate. At least a part of the first cladding layer and the second cladding layer has a superlattice structure comprising II-VI compound semiconductor. Another semiconductor light emitting device comprises a first cladding layer, a first guide layer, an active layer, a second guide layer and a second cladding layer which are stacked on semiconductor substrate. At least a part of the first cladding layer, the first guide layer, the second cladding layer and the second guide layer has a superlattice structure. Still another semiconductor light emitting device comprises a defect decomposing layer, a defect blocking layer, first cladding layer, an active layer, a second cladding layer which are stacked on a semiconductor substrate. The defect decomposing layer and the defect blocking layer comprise a superlattice structure.

Semiconductor light emitting device with defect decomposing and blocking

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Tokyo, Japan

Kazushi Nakano