Sumitomo Electric Industries, Limited

Sumitomo Electric Hardmetal Corp.

Naohiro Toda

Hitoshi Sumiya

Yoshiki Nishibayashi

Nobuhiko Fujita

Shin-ichi Shikata

Yutaka Kobayashi

Katsuko Yamamoto

Tadashi Tomikawa

Takeshi Sato

Shuichi Satoh

Akira Nakayama

Syoji Nakagama

An object is to provide polycrystalline diamond applicable to diverse applications; and a water jet orifice, a stylus for gravure printing, a scriber, a diamond cutting tool, and a scribing wheel that include such polycrystalline diamond. This object is achieved by polycrystalline diamond obtained by converting and sintering non-diamond carbon under an ultrahigh pressure and at a high temperature without addition of a sintering aid or a catalyst, wherein sintered diamond grains constituting the polycrystalline diamond have an average grain diameter of more than 50 nm and less than 2500 nm and a purity of 99% or more, and the diamond has a D90 grain diameter of (average grain diameter+average grain diameter&#xd7;0.9) or less.

Method of preparing polycrystalline diamond

A colorless, transparent low defect density, synthetic type IIa diamond single crystal, in which the etch pits due to needle-shaped defects are at most 3.times.10.sup.5 pieces/cm.sup.2, and which can be applied to uses needing high crystallinity of diamond, for example, monochromators, semiconductor substrates, spectroscopic crystals in X-ray range, electronic materials, etc., is provided by a process for the production of the colorless, transparent low defect density, synthetic diamond single crystal by growing new diamond crystal on a seed crystal of diamond by the temperature gradient method which comprises using a crystal defect-free diamond single crystal, as a seed crystal of diamond, and optionally subjecting to a heat treatment in a non-oxidizing atmosphere at a low pressure and a temperature of 1100 to 1600.degree. C.

Low defect density diamond single crystal and a process for the

An ohmic electorde of the present invention comprises a contact electrode layer formed on a p-type diamond semiconductor layer formed on a substrate so as to be in ohmic contact with the p-type diamond semiconductor layer and to have low contact resistance and high heat resistance, and a lead electrode layer formed on the contact electrode layer so as to have low lead wire resistance and high heat resistance. Specifically, the contact electrode layer is made of either a carbide of at least one metal selected from a metal group comprising Ti, Zr, and Hf, or a carbide of an alloy containing at least one metal selected from the metal group. Since the carbide of the metal or alloy forming the contact electrode layer is stabler in respect of energy because of reduced formation enthalpy than the metal or alloy itself, it is very unlikely to diffuse. Therefore, little metal or alloy forming the contact electrode layer precipitates on the surface of the lead electrode layer formed on the contact electrode layer, thus improving the device performance, based on the reduced lead wire resistance.

Ohmic electrode and method for forming it

A highly pure cubic boron nitride film is formed on a substrate by a method which comprises irradiating an excimer laser on a target comprising boron atoms and optionally nitrogen atom and depositing cubic boron nitride on a substrate which is placed to face the target.

Production of cubic boron nitride films by laser deposition

Growing community of inventors

Itami, Japan

Naohiro Toda