Kabushiki Kaisha Kobe Seiko Sho

Kobe Steel Usa, Inc.

Other

Kobe Steel USA Inc., Electronic Materials Center

Koichi Miyata

Koji Kobashi

Kimitsugu Saito

Kozo Nishimura

Kazuo Kumagai

Brian Rhys Stoner

David L Dreifus

Takeshi Tachibana

Yoshihiro Yokota

Shigeaki Miyauchi

Akimitsu Nakaue

Yuichi Matsui

Hiroyuki Tachibana

Yoshihiro Shintani

Takayoshi Inoue

Toshihisa Nozawa

Kohei Suzuki

Kalyankumar Das

Norio Suzuki

Jesko A Von Windheim

Yutaka Kawata

Scott R Sahaida

Yoshio Kawate

Hisashi Koyama

Kiyotaka Ishibashi

Kumar Das

John P Bade, Jr

Hisasi Koyamao

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.

Diamond films and methods for manufacturing diamond films

A method for microfabricating diamond includes the steps of: forming a resist layer composed of a ladder silicone spin-on glass material on the surface of diamond; performing lithography, in which the resist layer is irradiated with an electron beam or an ion beam in a given pattern; developing the resist layer to form the given pattern; and etching diamond by an ECR plasma etching method or a high-frequency plasma etching method.

Method for microfabricating diamond

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.

Methods for manufacturing monocrystalline diamond films

Disclosed is planar and vertical cold cathode emitter elements including an semiconducting diamond emitter portion having a high thermal resistance and a high breakdown voltage, thereby suppressing the deterioration of the electron emission characteristics and enabling the operation with a high electric power.

Cold cathode emitter element

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.

Methods for manufacturing substrates to form monocrystalline diamond

A diamond light-emitting element capable of intense light emission at low operation voltage. A conductive substrate is disposed on a metallic plate such as copper to form an ohmic contact. A first diamond layer is formed on the conductive substrate. The boron atom concentration in the first diamond layer is 10.sup.19 cm.sup.-3 or higher. A second diamond layer is formed on the first diamond layer. The second diamond layer has a crystal defect density of 10.sup.11 cm.sup.-2 or higher. A second electrode is formed on the second diamond layer. A power supply is connected to the second electrode and the copper plate. When voltage is applied, holes in the first diamond layer recombine with electrons from the second electrode, and hence light emission takes place. The defect levels in the second diamond layer form the recombination centers to achieve high brightness at low operation voltage.

Diamond light-emitting element

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.

Highly-oriented diamond film

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

The rectifying element is comprised of two electrodes, an undoped diamond film, and a B-doped p-type diamond film. The diamond films are formed of highly-oriented diamond films, of which at least 80% of the surface area consists of (100) or (111) crystal planes, and the differences {.DELTA..alpha., .DELTA..beta., .DELTA..gamma.} of Euler angles {.alpha., .beta., .gamma.}, which represent the orientations of crystal planes, simultaneously satisfy .vertline..DELTA..alpha..vertline..ltoreq.5.degree., .vertline..DELTA..bet a..vertline..ltoreq.5.degree. and .vertline..DELTA..gamma..vertline..ltoreq.5.degree. between adjacent crystal planes. The diamond rectifying element thus constructed have an excellent electrical characteristics, and multiple of the elements can be produced on a large area at low cost. The diamond rectifying elements can be used for heat-resistant and high-power rectifying elements.

Diamond rectifying element

A source electrode is formed on the first semiconducting diamond film and a drain electrode is formed on the second semiconducting diamond film. A highly resistant diamond film having a thickness of between 10 .ANG. and 1 mm and an electrical resistance of at least 10.sup.2 .OMEGA..cm or more is placed between the first and second semiconducting diamond films. A gate electrode is formed on the highly resistant diamond film. Thereby, a channel region is formed by these first and second semiconducting diamond films as well as the highly resistant diamond film. All or at least a part of said first and second semiconducting diamond films and the highly resistant diamond film are made of highly-oriented diamond films where either (100) or (111) crystal planes of diamond cover at least 80% of the film surface, and the differences {.DELTA..alpha., .DELTA..beta., .DELTA..gamma.} of Euler angles {.alpha., .beta., .gamma.} which represent the crystal plane orientation, satisfy .vertline..DELTA..alpha..vertline.&lt;10.degree., .vertline..DELTA..beta..vertline.&lt;10.degree., .vertline..DELTA..gamma..vertline.&lt;10.degree., simultaneously between adjacent crystal planes.

Highly-oriented diamond film field-effect transistor

An undoped highly-oriented diamond film is formed on a single crystalline silicon substrate, a p-type highly-oriented diamond film is formed on the insulating diamond film. An ohmic electrode is formed on said p-type semiconducting diamond film and an ohmic electrode is also formed on a n-type .beta.-SiC layer. The highly-oriented diamond films are grown by chemical vapor deposition and at least 80% of the surface area of said diamond film consists of either (100) or (111) crystal planes, and the differences {.DELTA..alpha., .DELTA..beta., .DELTA..gamma.} of Euler angles {.alpha., .beta., .gamma.}, which represent the orientations of the crystals simultaneously satisfy the following relations: .vertline..DELTA..alpha..vertline..ltoreq.5.degree., .vertline..DELTA..beta..vertline..ltoreq.5.degree. and .vertline..DELTA..gamma..vertline.5.degree. between adjacent crystal planes. The diamond hetero-junction rectifying element thus made has a high rectification ratio and heat resistance, and is suitable for mass production at low cost and on large scale.

Diamond hetero-junction rectifying element

A process of forming high quality diamond films, wherein non-diamond components and crystal defects are significantly reduced. Diamond films are formed on a diamond substrate by vapor-phase synthesis using a source gas, wherein the atomic concentrations of oxygen and carbon, [0] and [C], respectively, in the source gas satisfy the condition that 0.01.ltoreq.[C]/([C]+[O]).ltoreq.0.40. Boron (B) doped p-type semiconducting films can also be formed using the same source gas which further includes a B-containing compound.

Method of making a diamond film

A semiconducting diamond electroluminescence element comprises an electrically conductive substrate, a semiconducting diamond layer formed on the substrate, an insulating diamond layer formed on the semiconducting diamond layer, a front electrode formed on the insulating diamond layer, and a back electrode formed on the conductive substrate in ohmic contact with the same. The color of light to be emitted by the semiconducting diamond electroluminescence element can readily be determined by changing the impurity content in the semiconducting diamond layer. The luminescence intensity of the semiconducting diamond electroluminescence element can readily be changed by changing the voltage applied across the front and back electrodes without entailing dielectric breakdown.

Semiconducting diamond light-emitting element

A diamond film FET according to the present invention comprises a semiconducting diamond layer, a gate, a source, and a drain, wherein said semiconducting diamond layer comprises a semiconducting highly-oriented diamond film grown by chemical vapor deposition, and at least 80% of the surface area of said diamond film consists of either (100) or (111) crystal planes, and the differences {.DELTA..alpha., .DELTA..beta., .DELTA..gamma.} of Euler angles {.alpha., .beta., .gamma.}, which represent the orientations of either (100) or (111) crystal planes, simultaneously satisfy the following relations between the adjacent crystal planes: .vertline..DELTA..alpha..vertline..ltoreq.5.degree., .vertline..DELTA..beta..vertline..ltoreq.5.degree. and .vertline..DELTA..gamma..vertline..ltoreq.5.degree..

Highly oriented diamond film field-effect transistor

Disclosed is a method for forming a diamond film on a substrate by vapor-phase synthesis using a reaction gas which contains B.sub.2 H.sub.6 and O.sub.2 with a gas concentration ratio (volume %) of ([B.sub.2 H.sub.6 ]/[O.sub.2 ]).gtoreq.1.times.10.sup.-4 in addition to a hydrocarbon gas in hydrogen. By this invention, it is possible to form p-type semiconducting diamond films having an excellent crystallinity and desired electric characteristics.

Growing community of inventors

Kobe, Japan

Koichi Miyata