Hitachi, Ltd.

Other

Rikagaku Kenkyusko

Ushio Kawabe

Toshikazu Nishino

Yutaka Harada

Yoshinobu Tarutani

Mutsuko Hatano

Toshiyuki Aida

Tokuumi Fukazawa

Haruhiro Hasegawa

Mutsuko Miyake

Shinya Kominami

Yukio Honda

Kazumasa Takagi

Masaaki Aoki

Mikio Hirano

Shigehiko Yamamoto

Sadanori Taguchi

Masaaki Futamoto

Isamu Yuito

Nobuo Kotera

Shinichiro Yano

Shigeyuki Hosoki

Eiichi Goto

Atsushi Asano

Hideaki Nakane

Mitsuo Suga

Nobuo Miyamoto

Tohru Ishitani

Tokuo Kure

Hiroshi Okano

Masahiko Hiratani

Takahiko Kato

Fumio Murai

Hifumi Tamura

Akira Misumi

Yutaka Misawa

Kazuo Saitoh

Takao Kawamura

Mitsuhiro Kudo

Katsuzo Aihara

Yoshihide Wadayama

Katsuki Miyauchi

Jiro Kuniya

Tsutomu Komoda

Hirozi Yamada

Hiroshi Fukushima

Masahiro Ogihara

Kunio Yamashita

Shinichiroh Saitoh

Toshiyuki Aita

Yoshio Degawa

Norio Shibata

Yuji Hatano

Superconducting device include a type having a structure of a superconductor--a normal-conductor (or a semiconductor)--a superconductor, and a type having a superconducting weak-link portion between superconductors. The superconductors constituting the superconducting device are made of an oxide of either of perovskite type and K.sub.2 NiF.sub.4 type crystalline structures, containing at least one element selected from the group consisting of Ba, Sr, Ca, Mg, and Ra; at least one element selected from the group consisting of La, Y, Ce, Sc, Sm, Eu, Er, Gd, Ho, Yb, Nd, Pr, Lu, and Tb; Cu; and O. In addition, the c-axis of the crystal of the superconductor is substantially perpendicular to the direction of current flowing through this superconductor.

Superconducting device

Superconducting device having pinning regions

Disclosed are methods of forming superconducting devices including a type having a structure of a superconductor--a normal-conductor (or a semiconductor)--a superconductor, and a type having a superconducting weak-link portion between superconductors. The superconductors constituting the superconducting device are made of an oxide of either of perovskite type and K.sub.2 NiF.sub.4 type crystalline structures, containing at least one element selected from the group consisting of Ba, Sr, Ca, Mg, and Ra; at least one element selected from the group consisting of La, Y, Ce, Sc, Sm, Eu, Er, Gd, Ho, Yb, Nd, Pr, Lu, and Tb; Cu; and O. In addition, the c-axis of the crystal of the superconductor is substantially perpendicular to the direction of current flowing through this superconductor.

Method for forming high T.sub.c superconducting devices

A superconducting device low in power dissipation and high in operating speed is fabricated by use of a combination of a superconductor material and a semiconductor material. The superconducting device having a low power dissipation and high operating speed characteristic according to the present invention is suitable for configuring a large-scale integrated circuit.

A superconducting device has a structure of superconductor--normal--conductor (semiconductor)--superconductor. The superconducting regions and the normal-conductor region can be made of the same elements but having different relative proportions of the elements. The device can be fabricated by introducing at least one element into an unmasked region of the superconductor to form a normal conductor region or into unmasked regions of the normal conductor to form superconductor regions.

Method for forming a superconducting weak link device

A pair of superconducting electrodes are so formed as to interpose a semiconductor therebetween, and a control electrode is formed on the semiconductor through an insulator film so as to control the superconductive weak coupling state in the semiconductor between the superconducting electrodes. The distance between the superconducting electrodes is determined by the thickness of the superconductor interposed between the two electrodes, whereby the interelectrode distance is settled with a high precision to improve the uniformity of the device characteristic. And in an arrangement where two superconducting electrodes are formed on a semiconductor layer and the superconductive weak coupling state between such two electrodes is controlled by a third electrode, the gain is increadable by furnishing a varied impurity distribution in the semiconductor layer.

An oxide-superconducting device comprises first and second electrodes of oxide-superconductor which are connected through a tunnel barrier layer. The oxide-superconductor is formed on a substrate having a recess, and it includes grain boundaries along the recess. The tunnel barrier layer is formed along the grain boundaries, and it is made of any material of an element F, Cl, Br, I, C, O, S, P or N, a mixture consisting of such elements, and a compound containing such an element, the material being introduced into the grain boundaries and/or lattice interstices near the grain boundaries.

Oxide-superconduction grain boundary tunneling device

A superconducting device has a structure of superconductor - normal-conductor (semiconductor) - superconductor. The superconductors constituting the superconducting device are made of a superconducting oxide material of K.sub.2 NiF.sub.4 type crystal-line structure or perovskite type crystalline structure which contains at least one element selected from the group consisting of Ba, Sr, Ca, Mg and Ra; at least one element selected from the group consisting of La, Y, Ce, Sc, Sm, Eu, Er, Gd, Ho, Yb, Nd, Pr, Lu and Tb; Cu; and O.

Superconducting device having superconducting weak coupling

Superconducting device with C-axis orientation perpendicular to current

A superconducting field effect transistor which is very small in size and high in dimensional accuracy, has a first layer of material forming a control electrode and a second layer of another material is disposed on said first layer. A width of said first layer in a direction toward a superconducting source electrode and a superconducting drain electrode is narrower than a width of the second layer in the same direction. Polycrystalline silicon may be used as the control electrode while the second layer can be made of silicon nitride. Furthermore, a side surface of the control electrode may be coated with an insulator film. Accordingly, the above transistor has a fine structure gate electrode part that can be fabricated easily and accurately.

Superconducting field effect transistor

Superconducting electrodes are formed on a semiconductor which serves as a channel. A control electrode is disposed through an insulator film or a p-n junction on the side of the semiconductor which is opposite to the semiconductor side on which the superconducting electrode is formed. A superconducting current flows between the superconducting electrode across the semiconductor is controlled by an electric signal which is applied to the control electrode, thereby enhancing the current gain.

In a superconducting device wherein the value of a superconducting current to flow between two superconducting electrodes provided in contact with a semiconductor is controlled by a control electrode provided between the superconducting electrodes, high impurity concentration regions are formed within the semiconductor so as to lie in contact with the superconducting electrodes and to extend to under ends of the control electrode.

A superconductive element at least comprising first and second superconductive electrodes composed of an oxide superconductor material and a semiconductor film composed of an oxide semiconductor material put between the first and second superconductive electrodes and disposed in adjacent with the first and the second superconductive electrodes, in which the semiconductor film is formed with an oxide comprising rare earth elements other than Pr, Ba and Cu as the main ingredient element or an oxide comprising predetermined amount of rare earth elements other than Pr, predetermined amount of Pr, Ba and Cu as the main ingredient element. Extremely fine size is no more necessary to enable fabrication with the existent fine fabrication technic.

Superconductive switching element with semiconductor channel

A superconducting device has a structure of superconductor - normal-conductor (semiconductor) - superconductor. The superconductors constituting the superconducting device are made of a super-conducting oxide material of K.sub.2 NiF.sub.4 type crystalline structure or perovskite type crystalline structure which contains at least one element selected from the group consisting of Ba, Sr, Ca, Mg and Ra; at least one element selected from the group consisting of La, Y, Ce, Sc, Sm, Eu, Er, Gd, Ho, Yb, Nd, Pr, Lu and Tb; Cu; and O.

High T.sub.c superconducting device with weak link between two

Growing community of inventors

Tokyo, Japan

Ushio Kawabe