Kabushiki Kaisha Kobe Seiko Sho

Kazuo Kumagai

Koji Kobashi

Koichi Miyata

Shigeaki Miyauchi

Kozo Nishimura

Akimitsu Nakaue

Yuichi Matsui

Hiroyuki Tachibana

Takayoshi Inoue

Norio Suzuki

Yutaka Kawata

Yoshio Kawate

Rie Kato

Kiyotaka Ishibashi

Rie Katoh

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 method for forming diamond films by vapor phase synthesis comprising a process of forming the diamond films on a substrate by direct current discharge plasma, in an atmosphere of a reaction gas including a gas containing at least carbon and hydrogen, or in an atmosphere of a mixed gas containing at least a carbon-containing gas and a hydrogen gas, at a gas pressure between 0.1 and 5 Torr and a substrate temperature between 300.degree. and 1000.degree. C.

Method for forming diamond films by vapor phase synthesis

Thin diamond films can be selectively deposited imagewise on a substrate by gas phase synthesis. The substrate may be either a silicon substrate or a basal thin diamond film formed beforehand on a substrate by gas phase synthesis. Where a silicon substrate is used, its surface is first abraded to give a surface roughness suitable for gas phase synthesis of diamond. When a basal thin diamond film is used, a coating material capable of withstanding a temperature higher than a substrate temperature required for gas phase synthesis of diamond and having a high etching selectivity to diamond is needed to cover areas other than where the thin diamond film is to be newly formed. When a lift-off method is used, a thin masking film having a melting point higher than a temperature to be employed for gas phase synthesis of diamond can also be used in place of the coating material described above.

Process for the selective deposition of thin diamond film by gas phase

A diamond heterojunction diode having an improved rectifying characteristics with a small reverse current and a large forward current. Three layers are formed on a low-resistance p-type silicon substrate by the microwave plasma CVD in the order of a B-doped p type semiconducting diamond layer, an insulating undoped diamond layer (thinner than 1 .mu.m), and an n-type semiconducting silicon layer. Ohmic electrodes are formed on the front side of a n-type semiconducting silicon layer and the back side of a substrate. Under a forward bias, the electric field is applied to the intermediate insulating layer to accelerate the transport of holes and electrons. Under a reversed bias, the energy band has a notch as well as a potential barrier due to the intermediate layer thus preventing holes from transporting from the n-type semiconducting diamond layer to the p-type semiconducting diamond layer, resulting in the improved rectifying characteristics.

Diamond heterojunction diode

Described is an etching method of a diamond film which comprises providing a diamond film in an atmosphere of a gas containing at least oxygen and/or hydrogen and subjecting the diamond film to an irradiation of an electron beam generated by direct current discharge through a pattern of a mask. In this condition, when the diamond film is contacted with the plasma produced by the electron beam in the atmosphere, the unmasked areas are irradiated by the electron beam, and converted to graphite. The graphite is more readily etched by the plasma, so that the diamond film can be etched at a high rate. The etching through a mask ensures a fine etched pattern of the diamond film. In addition, a diamond film with a large area can be etched by this method.

Method of etching diamond thin films

Disclosed herein is a MIS type diamond field-effect transistor comprising a diamond semiconductor layer provided as an active layer by chemical vapor deposition (CVD), and a diamond insulator layer provided on the diamond semiconductor layer also by CVD, a gate electrode being formed on the diamond insulator layer, wherein a diamond insulator undercoat is provided on a non-diamond substrate by CVD, and the diamond semiconductor layer and the diamond insulator layer are sequentially provided on the diamond insulator undercoat. The MIS type diamond field-effect transistor with this structure ensures that in the manufacture thereof, a diamond insulator undercoat of large area can be formed on a non-diamond substrate of CVD, whereby a large number of elemental devices can be fabricated simultaneously.

MIS type diamond field-effect transistor with a diamond insulator

A schottky diode manufacturing process employing diamond film comprises forming a B-doped p-type polycrystalline diamond film on a low-resistance p-type Si substrate by CVD using a source gas consisting of CH.sub.4, H.sub.2 and B.sub.2 H.sub.6, forming an ohmic contact on the back of the p-type Si substrate, and forming a metal electrode of Al, Pt Au, Ti or W on the B-doped p-type polycrystalline diamond film. The B/C concentration ratio of the source gas is greater than 0.01 ppm and less than 20 ppm.

Schottky diode manufacturing process employing the synthesis of a

A diamond thin film thermistor having a substrate, an electrically insulating diamond layer formed on the substrate by vapor-phase synthesis, a semiconducting diamond layer as a temperature-sensing part on the electrically insulating diamond layer by vapor-phase synthesis, and metal thin film electrodes attached to the semiconducting diamond layer. A plurality of such diamond thin film thermistors can simultaneously be formed on a single substrate, and the substrate is cut with a dicing saw to provide individual diamond thin film thermistor chips of the same quality.

Diamond film thermistor

A plasma reactor for diamond synthesis includes a microwave generator, a waveguide connected to the microwave generator, an antenna disposed within the waveguide to direct the microwaves propagated along the waveguide toward the interior of a reaction chamber, a microwave window provided above the upper wall of the waveguide, a reaction chamber defined by (a) a cylindrical bottom member hermetically joined to the microwave window and the waveguide, (b) a reaction gas inlet port and a gas outlet port in the side wall thereof, and (c) a substrate holder disposed within the reaction chamber in facing opposition to the microwave window so as to be moved toward and away from the microwave window to adjust the distance between the microwave window and the substrate holder to generate a desired microwave resonance mode. A plasma is produced only in the central portion of the reaction chamber, so that the etching of the microwave window and the resulting contamination of the diamond film by impurities produced by etching the microwave window are prevented. The plasma reactor for diamond synthesis is capable of forming a high-quality diamond film on a large surface of a substrate at a high growth rate in a range of 1 to 2 .mu.m/hr.

Growing community of inventors

Kobe, Japan

Kazuo Kumagai