Hitachi, Ltd.

Hitachi Medical Corporation

Yoko Uchida

Minoru Yoshida

Hiromichi Yamada

Hideki Kohno

Atsushi Suzuki

Yasunari Umemoto

Hidetoshi Matsumoto

Shinichiro Takatani

Kenji Hiruma

Hiroshi Takagi

Yoichi Oba

Shigeo Goto

Takeshi Kikawa

Masamitsu Yazawa

Tadashi Fukino

Fukino Tadashi

Disclosed is a semiconductor device capable of suppressing the generation of dislocations due to the difference in lattice constant by insertion of one or more defect type compound layers in a semiconductor layered structure. The strain generated by the mismatch of the lattice is relaxed by a large amount of vacancies contained in the defect type compound layer, to suppress the generation and the propagation of dislocations, thus inexpensively fabricating a semiconductor device with less deterioration of the characteristics due to defects with good repeatability.

Semicoductor device having defect type compound layer between single

A field-effect transistor or a bipolar transistor may be provided in which the contact resistance between a channel layer or base layer and a contact layer are reduced. For example, an InGaAs buffer layer may be formed on the substrate side of an InGaAs channel layer of a field-effect transistor and by the bypassing effect that carriers pass through this InGaAs buffer layer, the InGaAs channel layer comes in contact with the contact layer with a low resistance. The contact resistance between the InGaAs channel layer and the contact layer can be reduced to 10 ohm per a width of 10.mu.m, and as a result, the value of transconductance factor K of a field-effect transistor can be increased in 14 mA/V.sup.2 per a width of 10.mu.m.

Semiconductor device having reduced contact resistance between a channel

A multielement scintillation radiation detector comprises a scintillator and a photosensitive detector, wherein to optically isolate between the adjacent radiation detectors, a thin light reflecting sheet on which a sponge material is attached is used to closely adhere to radiation shielding plates for partitioning each radiation detector.

Radiation detecting apparatus

In a radiation detector having a radiation-stimulated light emitting scintillator and a photodetector for receiving the light emission from the scintillator, the scintillator is formed of a layer of phosphor particles and a light scattering layer is provided in an optical path between the phosphor particle layer and the photodetector. Light generated in the surface of the scintillator is scattered and absorbed by the light scattering layer in some degree so that the reduced quantity of light incident upon the photodetector lowers the output of the photodetector. This effect is balanced with the lowering of the photodetector output due to the absorption and scattering of light generated at the inner parts of the scintillator and further removes anisotropic light emission. As a result, signal-to-noise ratio is greatly improved. A shielding layer between the scintillator and photodetector prevents secondary radiation such as scattered and fluorescent radiation from reaching the photodetector. The shielding layer can also serve as the scattering layer.

Radiation detector

A radiation detector comprising a scintillator exhibiting luminescence by the action of radioactive rays and a light detector detecting light output of said scintillator, characterized in that said scintillator is a phosphor represented by the formula:

A phosphor powder layer is formed by a process comprising a step of mixing a phosphor powder with a polymer emulsion and drying the mixture to give the phosphor powder coated with the polymer and a step of subjecting the phosphor powder coated with the polymer to heating and pressing. The resulting powder layer is suitable as a scintillator used in a radiation detector, particularly in a radiation detector used in X-ray CT.

Growing community of inventors

Kawasaki, Japan

Yoko Uchida