Abstract: A method for manufacturing a multilayered substrate for a semiconductor device, as well as a semiconductor device, is provided, the multilayered substrate exhibiting an excellent thermal conduction property and an excellent heat spreading effect without occurrence of warp and deformation. A diamond layer is formed through vapor phase deposition on one principal surface of a first silicon substrate by a CVD method. A SiO2 layer is formed on this diamond layer. A SiO2 layer is formed on a surface of a second silicon substrate by a thermal oxidation method. The diamond layer is bonded to the second silicon substrate with SiO2 layers disposed on both the diamond layer and the second silicon substrate therebetween. The first silicon substrate is removed by dissolution through etching to expose the surface of the diamond layer. A silicon layer serving as a semiconductor layer is formed on the diamond layer by a CVD method.

Abstract: A semiconductor device and package has a heat spreader directly disposed on the reverse surface of the semiconductor device. This heat spreader includes a diamond layer or a layer containing diamond and ceramics such as silicon carbide and aluminum nitride. The heat spreader is directly formed on a substrate for the semiconductor device. In particular, the heat spreader is composed of a diamond layer and one or two metal or ceramic members, which are bonded to the diamond layer with one or two polymer adhesive layers. This diamond layer has a fiber structure across the thickness or a microcrystalline structure. Cilia are formed on a surface of the diamond layer facing the one or two metal or ceramic members.

Abstract: A diamond semiconductor device includes a substrate made of single crystal diamond; a first diamond layer, placed on the substrate, containing an impurity; a second diamond layer containing the impurity, the second diamond layer being placed on the substrate and spaced from the first diamond layer; and a third diamond layer which has a impurity content less than that of the first and second diamond layers, which acts as a channel region, and through which charges are transferred from the first diamond layer to the second diamond layer. The first and second diamond layers have a first and a second end portion, respectively, facing each other with a space located therebetween. The first and second end portions have slopes epitaxially formed depending on the orientation of the substrate. The third diamond layer lies over the slopes and a section of the substrate that is located under the space.

Abstract: A highly-oriented diamond film which has a flat surface but does not have non-oriented crystals in the surface can be provided by depositing a first diamond layer on a substrate by {111} sector growth of diamond crystals by a CVD method using a gaseous mixture of methane and hydrogen as material gas, and then depositing a second diamond layer on the first diamond layer by {100} sector growth of diamond crystals by a plasma CVD method using a gaseous mixture of methane, hydrogen, and oxygen as material gas under the conditions that the pressure of the material gas is 133 hPa or more; the material gas composition is determined such that ([C]?[O])/[CH3+H2+O2] is ?0.2×10?2 or more and [O]/[C] is 1.2 or less; and the substrate temperature is between 750° C. and 1000° C.

Abstract: A diamond element is mounted on an insulating base material having a thickness of not more than 3 mm provided with one pair of metal interconnects. In the diamond element, an insulating diamond layer to act as a detection layer is deposited on a substrate, and one pair of interdigitated electrodes are deposited on the surface of this insulating diamond layer. The interdegital electrodes of the diamond element are connected via wires to the metal interconnects deposited on the insulating base material. The insulating base material may transmit ultraviolet radiation to be detected. The diamond sensor is capable of stably detecting ultraviolet radiation even when the distance between a lamp and an irradiation object is short.

Abstract: An ultraviolet sensor includes a substrate; a diamond layer, placed on the substrate, functioning as a detector; and at least one pair of surface electrodes arranged on the diamond layer. The diamond layer has a detecting region present at the surface thereof, the detecting region has at least one sub-region exposed from the surface electrodes, and the sub-region has a covering layer, made of oxide or fluoride, lying thereon. A method for manufacturing the ultraviolet sensor includes a step of forming a diamond layer, functioning as a detector, on a substrate; a step of forming at least one pair of surface electrodes on the diamond layer; and a step of forming a covering layer, made of oxide or fluoride, on at least one sub-region of a detecting region present at the surface of the diamond layer, the sub-region being exposed from the surface electrodes.

Abstract: A diamond semiconductor device includes a substrate made of single crystal diamond; a first diamond layer, placed on the substrate, containing an impurity; a second diamond layer containing the impurity, the second diamond layer being placed on the substrate and spaced from the first diamond layer; and a third diamond layer which has a impurity content less than that of the first and second diamond layers, which acts as a channel region, and through which charges are transferred from the first diamond layer to the second diamond layer. The first and second diamond layers have a first and a second end portion, respectively, facing each other with a space located therebetween. The first and second end portions have slopes epitaxially formed depending on the orientation of the substrate. The third diamond layer lies over the slopes and a section of the substrate that is located under the space.

Abstract: A semiconductor device and package has a heat spreader directly disposed on the reverse surface of the semiconductor device. This heat spreader includes a diamond layer or a layer containing diamond and ceramics such as silicon carbide and aluminum nitride. The heat spreader is directly formed on a substrate for the semiconductor device. In particular, the heat spreader is composed of a diamond layer and one or two metal or ceramic members, which are bonded to the diamond layer with one or two polymer adhesive layers. This diamond layer has a fiber structure across the thickness or a microcrystalline structure. Cilia are formed on a surface of the diamond layer facing the one or two metal or ceramic members.

Abstract: In the case of an engine automatic stop and start system in which an engine is stopped while a vehicle is stopped and the engine is started when the vehicle is started, it is necessary to shorten an engine starting time when a driver desires to move the vehicle. Further, it is desirable to efficiently compensate the electric power consumed by the starter. The vehicle contains an existing low voltage power source and a high voltage power source with an excellent charging efficiency. When the engine switches from a running condition to a stopped condition while the vehicle is stopped, a change-over switch switches and applies the voltage of the high voltage power source to a starter motor. This causes the starter motor to rotate at high speeds, thereby starting the engine very quickly. Therefore, it is possible to reduce overall energy losses and improve vehicle fuel consumption.

Abstract: In the case of an engine automatic stop and start system in which an engine is stopped while a vehicle is stopped and the engine is started when the vehicle is started, it is necessary to shorten an engine starting time when a driver desires to move the vehicle. Further, it is desirable to efficiently compensate the electric power consumed by the starter. The vehicle contains an existing low voltage power source and a high voltage power source with an excellent charging efficiency. When the engine switches from a running condition to a stopped condition while the vehicle is stopped, a change-over switch switches and applies the voltage of the high voltage power source to a starter motor. This causes the starter motor to rotate at high speeds, thereby starting the engine very quickly. Therefore, it is possible to reduce overall energy losses and improve vehicle fuel consumption.

Abstract: An organic LED is provided that can stably and efficiently emit light as a result of a heat resistant hole drift layer. The organic LED can include, in order, a substrate, a hole injection electrode layer, a hole drift layer, an organic light emitting layer, an electron drift layer and an electron injection electrode layer. The hole drift layer comprises a diamond film with a boron concentration of between about 1.0×1019 and about 1.0×1021/cm3. An optically transparent layer can be formed on the electron injection electrode layer.

Abstract: Diamond films and novel method to grow the diamond films can improve the performance of products utilizing diamond films. In the cathodoluminescence taken at room temperature, the integrated intensity ratio of the diamond films, CL.sub.1 /CL.sub.2, is equal or greater than 1/20, where CL.sub.1 is the integrated intensity of the emission band in the wavelength region shorter than 300 nm while CL.sub.2 is the integrated intensity of the emission band in the wavelength region from 300 nm to 800 nm. Such high quality diamond films with intensive coalescence on the surface can be obtained by deposition on the substrates or films, made of at least one member selected from the group consisting of platinum, platinum alloys, iridium, iridium alloys, nickel, nickel alloys, silicon, and metal silicides.

Abstract: Provided is a process for economically producing single crystal diamond film with a large surface area by gas-phase synthesis. The process comprises depositing platinum film or platinum alloy film containing more than 50 atomic % of platinum on a basal substrate with (111) or (001) surface while keeping the substrate temperature at 300.degree. C. or above, annealing the platinum or platinum alloy film at 1000.degree. C. or above, and performing the gas-phase synthesis of diamond using said platinum or platinum alloy film as the substrate.

Abstract: A method is related to grow monocrystalline diamond films by chemical vapor deposition on large area at low cost. The substrate materials are either bulk single crystals of Pt or its alloys, or thin films of those materials deposited on suitable supporting materials. The surfaces of those substrates must be either (111) or (001), or must have domain structures consisting of (111) or (001) crystal surfaces. Those surfaces can be inclined within .+-.10 degree angles from (111) or (001). In order to increase the nucleation density of diamond, the substrate surface can be scratched by buff and/or ultrasonic polishing, or carbon implanted. Monocrystalline diamond films can be grown even though the substrate surfaces have been roughened. Plasma cleaning of substrate surfaces and annealing of Pt or its alloy films are effective in growing high quality monocrystalline diamond films.

Abstract: A method is presented to manufacture substrates for growing monocrystalline diamond films by chemical vapor deposition (CVD) on large area at low cost. The substrate materials are either Pt or its alloys, which have been subject to a single or multiple cycle of cleaning, roller press, and high temperature annealing processes to make the thickness of the substrate materials to 0.5 mm or less, or most preferably to 0.2 mm or less, so that either (111) crystal surfaces or inclined crystal surfaces with angular deviations within .+-.10 degrees from (111), or both, appear on the entire surfaces or at least part of the surfaces of the substrates. The annealing is carried out at a temperature above 800.degree. C. The present invention will make it possible to markedly improve various characteristics of diamond films, and hence put them into practical use.

Abstract: The highly-oriented diamond film is a diamond film formed by chemical vapor deposition, with at least 95% of its area consisting of either (100) or (111) crystal planes, and the differences {.DELTA..alpha., .DELTA..beta., .DELTA..gamma.} of the Euler angles {.alpha., .beta., .gamma.} between the adjacent crystals satisfying (.vertline..DELTA..alpha..vertline..ltoreq.1.degree., .vertline..DELTA..beta..vertline..ltoreq.1.degree. and .vertline..DELTA..gamma..vertline..ltoreq.1.degree.) simultaneously. Thus obtained highly-oriented diamond film has few grain boundaries and high carrier mobility. And the area of the diamond film can be large.

Abstract: A method of forming a highly oriented diamond film having a reduced thickness with a high quality at a low cost. Surface of a single crystal substrate is cleaned, and is then left in a high vacuum of 10.sup.-6 Torr or less at a temperature between room temperature and 800.degree. C. for 15 min for releasing gas molecules absorbed on the surface of the substrate. The surface of the substrate is then processed using carbon-containing plasma for forming a barrier of obstructing a carbon component within the substrate. After that, an electric field is applied across the substrate and plasma for allowing a current to flow thereacross for a specified time, to form nuclei of diamond for synthesis of a diamond film. Thus, highly oriented diamond particles or films, in which crystal orientations thereof are epitaxial to the substrate, are synthesized.

Abstract: Disclosed is a heat-resistant ohmic contact formed on a semiconducting diamond. It has a contact Ti layer having a thickness of 10 to 70 .ANG. and a carbide layer generated by the reaction between the Ti layer and the semiconducting diamond layer. A diffusion prevention layer composed of at least one kind material selected from a group consisting of refractory metals including W, Mo, Au, Pt and Ta, refractory alloys including Ti-W, and refractory compounds including TiC and TiN is formed on the contact Ti layer. With this construction, the diffusion and the oxidation of Ti can be prevented.

Abstract: 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..

Abstract: A rectifying contact including a refractory metal carbide layer on a polycrystalline diamond layer provides high temperature operation and may be included in semiconductor devices, such as diodes and field effect transistors. The refractory metal carbide layer forms a substantially chemically non-reactive interface with the polycrystalline diamond. A single layer of substantially stoichiometric proportions of the refractory metal layer is provided in one embodiment of the rectifying contact. Another embodiment includes a second metal-rich refractory metal carbide layer on the stoichiometric layer. Yet another embodiment includes a carbon-rich refractory metal layer between the stoichiometric layer and the polycrystalline diamond layer. A metal field effect transistor including the rectifying contact may also be fabricated.