Tokyo Gas Company Limited

Japan Science and Technology Agency

Tokyo Gas Chemicals Co., Ltd.

Sumitomo Electric Industries, Limited

National Institute for Materials Science

Japan Science and Technology Corporation

Hiroshi Kawarada

Satoshi Yamashita

Takefumi Ishikura

Shin-ichi Ojika

Akira Hokazono

Naoji Fujimori

Takahiro Imai

Yoshiki Nishibayashi

Masahiro Itoh

Hitoshi Umezawa

Yoshihiko Takano

Kensaku Kobayashi

Masanori Nagao

Minoru Tachiki

Naofumi Nakamura

A heavily boron-doped diamond thin film having superconductivity is deposited by chemical vapor deposition using gas mixture of at least carbon compound and boron compound, including hydrogen. An advantage of the diamond thin film deposited by the chemical vapor deposition is that it can contain boron at high concentration, especially in (111) oriented films. The boron-doped diamond thin film deposited by the chemical vapor deposition shows the characteristics of typical type II superconductor.

Superconductivity in boron-doped diamond thin film

A DNA sensor including a p-channel field-effect transistor having as a gate an electrolyte solution and having as a channel a diamond surface which contains a mixture of at least a hydrogen-terminated surface and a surface terminated by an amino group or a molecule with an amino group as an amino termination; a probe DNA constituted of a single-stranded DNA with known nucleotide sequence which is directly immobilized by a linker to the amino termination of the diamond surface; and a target DNA constituted of an unknown single-stranded DNA which is dropped on said diamond surface, wherein the hybridization of the target and probe is ascertained by detecting a shift of the threshold voltage of said p-channel field effect transistor toward positive direction which is due to increase in hole density of the p-channel resulting from doubling the negative electric charge of the phosphate groups upon hybridization.

DNA sensor

A p channel field effect transistor in which the sensitivity of an enzyme can be enhanced by immobilizing the enzyme directly on an FET channel surface (diamond surface), as well as a sensor including the same, is provided. A diamond surface () having mixed hydrogen terminals, oxygen terminals, and amino terminals is treated under the action of glutaraldehyde OHC(CH)CHO (), so that the glutaraldehyde () is immobilized on the diamond surface () having mixed hydrogen terminals, oxygen terminals, and amino terminals. Subsequently, urease () is further applied thereto, so that the amino group () of the urease () is bonded to the glutaraldehyde (). That is, the urease () can be immobilized on the diamond surface () having mixed hydrogen terminals, oxygen terminals, and amino terminals. When the urea concentration is increased from 10M to 10M, the threshold voltage shifts by about 0.1 V in the positive direction, and the sensitivity to urea concentration of 30 mV/decade is exhibited.

p channel filed effect transistor and sensor using the same

Field-effect transistor

There is provided a diamond crystal in which the (111) oriented plane is of the diamond crystal synthesized on a substrate by a chemical vapor deposition method parallel to a substrate surface, and the area of the (111) oriented plane parallel to the substrate surface is 1/24or less an area of the crystal on the substrate. A source gas is activated on a substrate consisting of a material which is not reactive with carbon. The source gas contains at least carbon and hydrogen in such a manner that the ratio of the number of carbon atoms to the total number of molecules of the source gas is 0.5% or less. Subsequently, a diamond crystal in which the (111) orientation plane is parallel to the substrate surface, and the area of the (111) orientation plane parallel to the substrate surface is precipitated on the substrate. A copper plate is preferably contains used as the substrate. The source gas preferably contains at least methane gas and hydrogen gas, and the concentration of methane gas is preferably set to be 0.5% or less.

CVD method of manufacturing diamond crystal

On the surface of a hydrogen-terminated diamond 1 formed by terminating a surface 2 of either a homoepitaxial diamond or a heteroepitaxial diamond or a surface-flattened polycrystal diamond are formed a drain-ohmic contact 4 and a source-ohmic contact 3 of gold or platinum, an insulating layer 5 formed of silicon oxide (SiO.sub.x : 1.ltoreq.X.ltoreq.2) and a gate electrode 6 mounted on said insulating layer, and the surface other than the element forming region is set to be an insulating region being non-hydrogen-terminated, for example, oxygen-terminated, and the elements formed on said region is being isolated.

Hydrogen-terminated diamond MISFET and its manufacturing method

Hydrogen-terminated diamond misfet and its manufacturing method

There is provided a diamond crystal in which the (111) oriented plane is of the diamond crystal synthesized on a substrate by a chemical vapor deposition method parallel to a substrate surface, and the area of the (111) oriented plane parallel to the substrate surface is 1/24 or less an area of the crystal on the substrate.

Diamond crystal

A diamond semiconductor device having at least one MESFET integrated on a single diamond substrate and insulated from other semiconductor elements is made by preparing a homoepitaxial diamond film 1 having a hydrogen-terminated surface; then making a drain ohmic contact 3, a source ohmic contact 4, both of gold, and a gate electrode 5 of aluminum on the film 1; and changing a site of the hydrogen-terminated surface other than the site for the MESFET to be terminated with atoms other than hydrogen atoms.

Element-isolated hydrogen-terminated diamond semiconductor device and

A solid state laser includes a diamond crystal as a medium of laser beam emission, which generates a laser beam having a wavelength of 225 to 300 nm through exciton light emission.

Growing community of inventors

Yokohama, Japan

Hiroshi Kawarada