Kobe Steel Usa, Inc.

Other

Jesko A Von Windheim

Koji Kobashi

Brian Rhys Stoner

David L Dreifus

Kazushi Hayashi

Bradley A Fox

Vasudev Venkatesan

Koichi Miyata

Kimitsugu Saito

Takeshi Tachibana

Scott R Sahaida

John P Bade, Jr

An acceleration sensor includes an acceleration mass and a substrate mounted so that a cavity is defined therebetween and so that the acceleration mass moves relative to the substrate when an acceleration of the sensor changes. The sensor also includes a diamond field emitter for generating an electron beam through the cavity between the acceleration mass and the substrate. Accordingly, the distance between the acceleration mass and the substrate affects the current of the electron beam which is measured to determine the acceleration of the sensor. The sensor may alternately include an annular extraction electrode in a cavity between a substrate and a collector together with a diamond field emitter for generating an electron beam which passes through the annular extraction electrode. The annular extraction electrode is moveable relative to the substrate in response to changes in an acceleration acting on the sensor. Accordingly, the electron beam current changes as the annular extraction electrode moves, and the current can be measured to determine the acceleration acting on the sensor.

Diamond field emission acceleration sensor

A semiconductor device for providing stable operation over a relatively wide temperature range includes a wide bandgap semiconductor active region having an intentional dopant of a first conductivity type and an unintentional impurity of a second conductivity type which together produce a free carrier concentration at room temperature. The concentration of the intentional dopant in the active region is preferably less than 1.times.10.sup.16 cm.sup.-3 and the concentration of the unintentional impurity is less than 0.1 times the intentional dopant concentration so that the intentional dopant concentration will be less than 1000 times the free carrier concentration at room temperature. The intentional dopant concentration supplies substantially all the majority free carriers in the active region. The wide bandgap semiconductor active region is preferably diamond, IV-IV carbides, III-V nitrides and phosphides and II-VI selenides, tellurides, oxides and sulfides. By lightly doping the active region to a level below 1.times.10.sup.16 cm.sup.-3, relatively uniform device characteristics can be achieved over a wide temperature range extending from room temperature to 1000 K and above.

Wide bandgap semiconductor device including lightly doped active region

The present invention relates to a heat dissipating substrate with a highly-oriented diamond film of a low crystal inclination and a low density grain boundaries and having a significantly high thermal conductivity. At least 90% of the surface area of the highly-oriented diamond film is covered with either (100) or (111) crystal planes, and the differences {.DELTA..alpha., .DELTA..beta., .DELTA..gamma.} of the Euler angles, which represent the orientations of the crystals, between adjacent (100) or (111) crystal planes, simultaneously satisfies the following relationship: .vertline..DELTA..alpha..vertline..ltoreq.5.degree., .vertline..DELTA..beta..vertline..ltoreq.5.degree., and .vertline..DELTA..gamma..vertline..ltoreq.5.degree.. In addition, this highly-oriented diamond film can be grown on a non-diamond substrates, and therefore the diamond film with a large surface area can be obtained. Thus, the present invention provides the heat dissipating substrate with an excellent thermal conductivity at low cost.

Highly-oriented diamond film heat dissipating substrate

The highly-oriented diamond film thermistor has a temperature sensing part formed of a highly-oriented diamond film grown by chemical vapor deposition. This highly-oriented diamond film satisfies the conditions that at least 65% of the film surface area is covered by (100) or (111) planes of diamond and the differences {.DELTA..alpha., .DELTA..beta., .DELTA..gamma.} of Euler angles {.alpha., .beta., .gamma.}, which represent the orientations of the crystal planes, simultaneously satisfy conditions, .vertline..DELTA..alpha..vertline..ltoreq.5.degree., .vertline..DELTA..beta..vertline..ltoreq.5.degree., .vertline..DELTA..gamma..vertline..ltoreq.5.degree., between adjacent crystal planes.

Highly-oriented diamond film thermistor

A magnetic sensor element using highly-oriented diamond film comprises a magnetic detecting part, at least a pair of main current electrodes for flowing a main current and generating the Hall electromotive force at the magnetic detecting part, and detection electrodes for detecting said Hall electromotive force. Said magnetic detecting part is formed of a highly-oriented diamond film grown by chemical vapor deposition, at least 90% of which consists of either (100) or (111) crystal planes. Between the adjacent crystal planes, the differences {.DELTA..alpha., .DELTA..beta., .DELTA..gamma.} of the Euler angles {.alpha., .beta., .gamma.} which represent the orientation of the crystal planes, satisfy the following relations simultaneously: .vertline..DELTA..alpha..vertline..ltoreq.10.degree., .vertline..DELTA..beta..vertline..ltoreq.10.degree. and .vertline..DELTA..gamma..vertline..ltoreq.10 .degree.. The magnetic sensor element using highly-oriented diamond film has a high heat stability and sufficiently high level of magnetic field sensitivity to be used practically, enabling to expand the surface area and to increase the integration of the element and to measure magnetic field over a wide area and a large space.

Magnetic sensor element using highly-oriented diamond film and magnetic

A chemical sensor includes a diode or a transistor fabricated in diamond. A diamond-based diode chemical sensor includes a first diamond layer of first conductivity type and a second diamond or non-diamond layer of second conductivity type. A relatively highly doped region is formed in the first diamond layer, adjacent an electrical contact to reduce the frequency dependance of the sensor's capacitance/voltage characteristic. A diamond-based transistor sensor includes a controlling electrode such as a gate which is configured to allow a chemical external to the transistor to alter the characteristics of the transistor. Relatively highly doped regions are formed adjacent the transistor's controlling electrodes, such as the source and drain. A heater is thermally coupled to the sensor for heating the sensor to a predetermined operating temperature. A temperature monitor is also coupled to the sensor for monitoring the sensor temperature.

Diamond-based chemical sensors

Schottky diodes and gas sensors include a diamond layer having a Schottky contact thereon and an ohmic contact thereon, wherein the diamond layer includes a highly doped region adjacent the ohmic contact to provide a low resistance ohmic contact. Dramatically reduced frequency dependence of the capacitance/voltage characteristic of Schottky diodes and gas sensors formed thereby, compared to Schottky diodes and gas sensors which do not include the highly doped region adjacent the ohmic contact, is provided. The highly doped region is preferably boron doped at a concentration of at least 10.sup.20 atoms per cubic centimeter to form an ohmic contact with a contact resistance of less than 10.sup.-3 .OMEGA.-cm.sup.2. The ohmic contact is preferably a back contact on the face of the diamond layer opposite the Schottky contact.

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Raleigh, NC, United States of America

Jesko A Von Windheim