International Superconductivity Technology Center

Hokkaido Electric Power Company, Inc.

Oki Electric Industry Co., Ltd.

The Chugoku Electric Power Co., Inc.

Mitsubishi Electric Corporation

Nippon Steel Corporation

Mitsubishi Materials Corporation

Mitsubishi Metal Corporation

Norio Homma

Tadataka Morishita

Hiromi Takahashi

Hideyuki Kondo

Shinji Kawamoto

Yukihisa Yoshida

Wataru Ito

Tadataka Horishita

Disclosed is a method of forming a thin junction film including a first thin oxide flilm presenting a superconductivity and second thin oxide film presenting an insulator properties or possibly semiconductive properties with an improved production efficiency as well as improved film quality and characteristics. Employed are first and second targets each having substantially the same chemical composition excepting oxygen content. The first target is sputtered at a target cathode voltage of minus 100 V by the use of voltage derived from an external D.C. voltage source, thereby forming a first thin oxide film. Subsequently, the target is changed over to the second target while changing the target cathode voltage into self-bias voltage of minus 50 V without any change of the other film formation conditions. Through this change-over, the sputtering of the first target is successively followed by the sputtering of the second target without any interruption of time, to consequently form the second thin oxide film onto the first thin oxide film.

Process for forming a semiconductive thin film containing a junction

A method of making a superconducting thin film of a Y--Ba--Cu--O series material by using a diode parallel plate type sputtering apparatus including a vacuum chamber, a substrate disposed within the vacuum chamber and having a substantially flat surface on which the superconducting thin film is to be formed, and a plate-shaped target functioning as a cathode and disposed within the vacuum chamber to parallelly face to the flat surface of the substrate, the target being made of the same material as the superconducting thin film, a plasma gas being introduced into the vacuum chamber, and a voltage being applied between the cathode and the substrate, wherein the method comprises the steps of applying a high frequency voltage having a frequency higher than 40 MHz between the cathode and the substrate to generate plasma of the introduced gas, superimposing a DC voltage (V) on the high frequency voltage in a polarity that the cathode becomes negative, and setting the DC voltage at a value where the DC voltage is substantially unchanged with variation of a cathode current flowing through the target when adjusting the DC voltage and controlling a value of the DC current while maintaining the DC voltage substantially at the set value.

Method of making an oxide superconducting thin film

A process for forming a thin oxide film on an underlying surface adapted for film formation thereon according to a radio frequency magnetron sputtering method using an oxide target(s). The excitation frequency is a frequency which is higher than 13.56 MHz and which provides a negative target self-bias voltage permitting of film formation.

Process for forming thin oxide film

A process for forming a thin oxide film on an underlying surface adapted for film formation thereon according to a radio frequency magnetron sputtering method using an oxide target(s). The excitation frequency is higher than 13.56 MHz and provides a lower negative target self-bias voltage permitting improved film formation.

Growing community of inventors

Tokyo, Japan

Norio Homma