National Research Institute for Metals

Fujitsu Corporation

Kikuo Itoh

Kyoji Tachikawa

Yuji Furumura

Fumitake Mieno

Takashi Eshita

Masahiko Doki

Yasuo Iijima

Hisashi Sekine

A silicon carbide layer between a silicon substrate or layer and a metal layer because silicon carbide has many properties similar to those of silicon, has a very slow diffusion rate of a metal through the silicon carbide, or prevents a diffusion of a metal into the silicon, and can be deposited by CVD, which has an advantage of a good coverage over a step portion such as a contact window.

Silicon carbide barrier between silicon substrate and metal layer

A single crystalline silicon carbide (.beta.-SiC) layer having a thickness greater than 1 .mu.m is grown on a silicon substrate by the following method of the present invention. The silicon substrate is provided in a reactor chamber, and the reactor chamber is evacuated and maintained at a reduced atmospheric pressure during the growing processes. While flowing a mixed gas containing acetylene into the reactor chamber, the substrate is heated up at a temperature range from 800.degree. to 1000.degree. C., preferable in a range from 810.degree. to 850.degree. C., whereby a buffer layer of carbonized silicon having a thickness of 60 to 100 .ANG. is grown on the substrate. Thereafter, the flowing gas is changed to a mixed gas containing hydrocarbon and chlorosilane, and the substrate temperature is raised to a temperature from 850.degree. to 950.degree. C. In this process, a single crystalline .beta.-SiC layer can be grown on the buffer layer, and a thickness of a few .mu.m for the grown .beta.-SiC layer can be expected.

Method of growing a single crystalline .beta.-SiC layer on a silicon

In a process for producing at least one Nb.sub.3 Sn superconductor which comprises drawing a composite composed of a core of niobium or a niobium alloy and a matrix of a copper-tin alloy and subjecting the drawn composite to reactive heat-treatment, thereby forming a layer of Nb.sub.3 Sn between the core and the matrix; the improvement wherein the copper-tin alloy contains 1 to 15 atomic percent of tin, and 0.1 to 8 atomic percent in total of at least one element selected from 0.1 to 8 atomic percent of titanium, 0.1 to 5 atomic percent of zirconium and 0.1 to 5 atomic percent of hafnium.

Process for producing Nb.sub.3 Sn superconductor

A superconductor including V.sub.3 Ga is produced by making a composite of a vanadium core metal, a continuous portion of aluminum surrounding the vandium core metal or forming a second core, and a copper, silver or copper-silver alloy containing gallium, fabricating the composite to the desired shape, and heat-treating the shaped composite. The vanadium core may contain titanium, zirconium or hafnium, and the continuous portion of aluminum may contain copper or zirconium.

Method for producing composite superconductors

A superconductor including V.sub.3 Ga is produced by making a composite of a vanadium core metal, a continuous portion of aluminum surrounding the vanadium core metal or forming a second core, and a copper, silver or copper-silver alloy containing gallium, fabricating the composite to the desired shape, and heat-treating the shaped composite. The vanadium core may contain titanium, zirconium or hafnium, and the continuous portion of aluminum may contain copper or zirconium.

Growing community of inventors

Yokohama, Japan

Kikuo Itoh