Toyota Jidosha Kabushiki Kaisha

Idemitsu Kosan Company, Limited

Nachi - Fujikoshi Corporation

Yasuyuki Fujiwara

Yukio Terashima

Toshiaki Tanaka

Masazumi Onishi

Atsushi Danno

Noritaka Miyamoto

Akinori Seki

Hidemitsu Sakamoto

Hironori Daikoku

Kenichi Yamaguchi

Katsumi Ichitani

Izuru Yamamoto

Masahiro Kobessho

Makoto Takeishi

Shintaro Igarashi

Yoshinari Tsuchiya

Masatoshi Sawamura

Shinichi Nagamori

Yoshimi Aoyama

A method for producing n-type SiC single crystal, including: adding gallium and nitrogen, which is a donor element, for obtaining an n-type semiconductor during crystal growth of SiC single crystal, such that the amount of nitrogen as represented in atm unit is greater than the amount of gallium as represented in atm unit; an n-type SiC single crystal obtained according to this production method; and, a semiconductor device that includes the n-type SiC single crystal.

Production method of n-type SiC single crystal, n-type SiC single crystal obtained thereby and application of same

In a method of producing a SiC single crystal, the SiC single crystal is grown on a SiC seed crystal by bringing the SiC seed crystal, which is fixed at a rotatable seed crystal fixing shaft, into contact with a solution produced by dissolving carbon in melt containing silicon in a rotatable crucible. The method includes starting rotation of the seed crystal fixing shaft, and starting rotation of the crucible after a predetermined delay time (Td); then stopping the rotation of the seed crystal fixing shaft and the rotation of the crucible simultaneously; then stopping the seed crystal fixing shaft and the crucible for a predetermined stop time (Ts); and repeating a rotation/stop cycle.

Method of producing SiC single crystal

In a method for growing a silicon carbide single crystal on a silicon carbide single crystal substrate by contacting the substrate with a solution containing C prepared by dissolving C into the melt that contains Cr and X, which consists of at least one element of Ce and Nd, such that a proportion of Cr in a whole composition of the melt is in a range of 30 to 70 at. %, and a proportion of X in the whole composition of the melt is in a range of 0.5 at. % to 20 at. % in the case where X is Ce, or in a range of 1 at. % to 25 at. % in the case where X is Nd, and the silicon carbide single crystal is grown from the solution.

Method for growing silicon carbide single crystal

A method for growing a silicon carbide single crystal on a single crystal substrate comprising the steps of heating silicon in a graphite crucible to form a melt, bringing a silicon carbide single crystal substrate into contact with the melt, and depositing and growing a silicon carbide single crystal from the melt, wherein the melt comprises 30 to 70 percent by atom, based on the total atoms of the melt, of chromium and 1 to 25 percent by atom, based on the total atoms of the melt, of X, where X is at least one selected from the group consisting of nickel and cobalt, and carbon. It is possible to improve morphology of a surface of the crystal growth layer obtained by a solution method.

In a method for growing a p-type SiC semiconductor single crystal on a SiC single crystal substrate, using a first solution in which C is dissolved in a melt of Si, a second solution is prepared by adding Al and N to the first solution such that an amount of Al added is larger than that of N added, and the p-type SiC semiconductor single crystal is grown on the SiC single crystal substrate from the second solution. A p-type SiC semiconductor single crystal is provided which is grown by the method as described above, and which contains 1&#xd7;10cmof Al and 2&#xd7;10to 7&#xd7;10cmof N as impurities.

Method for growing p-type SiC semiconductor single crystal and p-type SiC semiconductor single crystal

A seed crystal axis used in a solution growth of single crystal production system is provided to prevent formation of polycrystals and grow a single crystal with a high growth rate. The seed crystal axis includes a seed crystal bonded to a seed crystal support member between which is interposed a laminated carbon sheet having a high thermal conductivity in a direction perpendicular to a solution surface of a solvent. The laminated carbon sheet includes a plurality of carbon thin films laminated with an adhesive or a plurality of pieces with differing lamination directions arranged in a lattice. Alternatively, a wound carbon sheet including a carbon strip wound concentrically from the center or a wound carbon sheet including a plurality of carbon strips with differing thicknesses which are wound and laminated from the center may be provided.

Seed crystal axis for solution growth of single crystal

In a method for growing a silicon carbide single crystal on a silicon carbide single crystal substrate by contacting the substrate with a solution containing C by dissolving C into the melt that contains Si, Cr and X, which consists of at least one element of Sn, In and Ga, such that the proportion of Cr in the whole composition of the melt is in a range of 30 to 70 at. %, and the proportion of X is in a range of 1 to 25 at. %, and the silicon carbide crystal is grown from the solution.

A method for producing a p-type SiC semiconductor single crystal, including: using a solution in which C is dissolved in a Si melt and 30 to 70 at. % Cr and 0.1 to 20 at. % Al, based on a total weight of the Si melt, Cr, and Al, are added to the Si melt, to grow a p-type SiC semiconductor single crystal on a SiC single crystal substrate from the solution.

Method for producing p-type SiC semiconductor single crystal

The heat-treating oil composition of the present invention is characterized by comprising a mixed base oil containing a low-boiling base oil having a 5% distillation temperature of from 300 to 400&#xb0; C. in an amount of not less than 5% by mass but less than 50% by mass, and a high-boiling base oil having a 5% distillation temperature of 500&#xb0; C. or higher in an amount of more than 50% by mass but not more than 95% by mass. There is provided a quenching oil composition capable of exhibiting a less fluctuation in hardness or quenching distortion of a metal material treated therewith even when a large number of the metal materials are quenched therewith at the same time.

Heat treatment oil composition

A multistage gear-rolling apparatus of the present invention comprises a roller squeezing apparatus including a roughing roller die and a finishing roller die disposed coaxially and connected in series in an axial direction of said roughing roller die. The roughing roller die is used for carrying out a hot rough-rolling step. The finishing roller die is used for a warm finish-rolling step. Thus, immediately after the hot rough-rolling step, the warm finish-rolling step can be carried out without a reset of workpiece.

Multistage gear-rolling apparatus

According to the present invention, in a heating step, an outer circumferential portion of a workpiece having a disk shape is heated to high temperatures. In a hot rough-rolling step, the outer circumferential portion of the heated workpiece is formed by use of a roller die to generate a rolled-gear having teeth. In a warm finish-rolling step, the teeth of the rolled-gear are finish-rolled by use of the finishing roller die. The starting temperature T.sub.1 of the hot rough-rolling step is set in the range of from 850.degree. through 1100.degree. C., the terminating temperature of the hot rough-rolling step T.sub.2 is set in the range of from 500.degree. through 700.degree. C. The starting temperature T.sub.3 of the warm finish-rolling step is set in the range of from 400.degree. through 700.degree. C., and the terminating temperature of the warm finish-rolling step T.sub.4 is set in the range of from 200.degree. through 650.degree. C.

Process for gear-rolling a high accuracy gear

A method for producing cast iron gears includes the steps of heating a blank composed of cast iron and having a teeth forming part to such a temperature that at least the teeth forming part is at least austenitized, and hot rolling the teeth forming part of the blank by pressing projecting teeth of a rolling machine against the teeth forming part which is in a hot state and within an austenitized range, while cooling the blank, thereby generating a teeth part in the teeth forming part of the blank. Hot rolling with a low plastic deformation resistance prevents lowering of strength due to the exposure of graphite particles of cast iron and occurrence of quenching cracks and rolling cracks, and improves gear accuracy.

Growing community of inventors

Shizuoka-ken, Japan

Yasuyuki Fujiwara