Site: International Superconductivity Technology Center (ISTEC)
Superconductivity Research Laboratory (SRL)
1-10-13 Shinonome, Koto-ku
Tokyo 135, Japan
Tel: 813-3536-5703; Fax: 5714
http://www.sendai.kopas.co.jp/ISTEC
Date Visited: January 27, 1997
WTEC Attendees: J. Rowell (report author), M. Beasley, G. Gamota, H. Morishita, M. Nisenoff, F. Patten, R. Ralston
Hosts: Dr. Shoji Tanaka, Director General, SRL
Masatoshi Toriihara, Senior Managing Director, ISTEC
Dr. Yoichi Enomoto, Director, Division VI, SRL
Dr. Tetsuji Kobayashi, Director, International Affairs Department, ISTEC
Dr. Naoki Koshizuka, Deputy Director General; Director, Division I, SRL
Katsuya Ogiso, Managing Director and Secretary General, ISTEC
Dr. Katsumi Suzuki, Group Leader of High Speed Device Application, Senior Research Scientist, Division VI, SRL

BACKGROUND

Following the discovery of the high temperature superconductors, a number of different projects were begun by MITI in Japan to support HTS research for 10 years (April 1988-1998). Both the topics and the structure of the projects varied. For example, the electronics project was performed in individual industry laboratories with support from the Future Electron Devices (FED) organization. ISTEC represents a very different structure for collaborative research. Perhaps the closest similar example in the United States is MCC in Austin, Texas.

ISTEC was established by MITI as a nonprofit foundation in January 1988. Its four major functions were to undertake surveys and studies of global trends in superconductivity technologies and their feasibility; to carry out basic research and development particularly with a materials and processing emphasis; to be a center for education and information dissemination; and to encourage international exchange through workshops and postdoctoral sponsorship.

R&D FUNDING

Funding for ISTEC is provided by MITI and by industry. The 103 (as of April 1996) industrial participants fall into two groups, "special" and "ordinary," depending on the level of their financial contributions. Of the 11 non-Japanese members (6 are American), only DuPont is in the special category.

The research of ISTEC is carried out in four laboratories to which the industry participants send their scientists. A new central laboratory was built in Koto-Ku, Tokyo, and three other laboratories use rented space in Tamachi, Nagoya, and Marioka. The research arm is the Superconductivity Research Laboratory, SRL, which is divided into 9 research divisions, of which 7 have representatives at the main central laboratory in Tokyo.

The budget of ISTEC is from MITI (NEDO) and from the industrial partners. The "special" partners have contributed ¥4.7 billion (($39 million) over 9 years in "start-up" funds as they joined. NEDO funding has steadily increased and in 1996 was ¥2.37 billion (($20 million). Likewise, the number of personnel increased overall, from 118 in 1989 (after the initial steep growth phase) to 190 in 1996; however, the number of "dispatched researchers" (those from industry) declined from 95 to 79 in this period. The increases have been in visiting researchers (1 to 18), in employed researchers (5 to 19), in students (0 to 37), and in administrative staff (10 to 25). Thus, the growth of ISTEC has not been because of increased industrial participation. The total budget averaged roughly $25 million per year over the last 3 years (1994-96) of Phase 1. The total ISTEC budget for the first 10 years of the project, from MITI and industry, will be about ¥28 billion, or close to a quarter of a billion dollars per year.

At the time of the WTEC panel's visit, ISTEC had had over 250 participants from industry; 37 of those received PhDs for the work they performed there. Over 350 patents had been granted to ISTEC. Visiting researchers from outside Japan totaled 65, with the largest numbers coming from China (14), Germany (9), Korea (8), the UK (7) and the United States (7).

During the panel's visit, Dr. Tanaka reviewed recent trends in superconductivity research activities at ISTEC. Then Masatoshi Toriihara gave a broad description of superconductivity research in Japan. He pointed out that 51 companies were involved in superconductivity in Japan and, in contrast to the United States, these are mainly large companies, with 35% having revenues of a trillion yen or more. Many of the superconductivity groups are small, however, with 50% having less than 10 people, and 25% less than 5. Industrial research budgets have decreased since 1992. In contrast, total government expenditures on superconductivity increased steadily from 1988 to reach $200 million/year in 1996. The distribution across agencies is roughly MITI 50%, STA 25%, and the Ministry of Transportation (for the levitated train project) 25%. Since 1994 Japan has spent more per year on superconductivity research than the United States, according to the budget numbers presented by Toriihara. He then spent some time in a most interesting description of the 1995 "Science and Technology Basic Law," which will result in further funding increases for some areas of basic research.

In the formal meeting of the afternoon and during the informal conversations during the most pleasant dinner that followed, the future of ISTEC was the major topic. The first 10-year project ended in March 1998, and planning for ISTEC Phase 2 had obviously been underway for some time when the WTEC team visited in January 1997. Phase 2 was subsequently funded by MITI for 5 years at a level of ¥4 billion/year, with a possible further 5-year extension to 2008. To hear of such long-term planning as a reality was of course quite alien for the U.S. team, but was accepted as normal by our Japanese hosts.

R&D ACTIVITIES

The research directions of ISTEC Phase 2 seem to be an extension of some of the changes that have already been taking place in Phase 1. Over the past 10 years, the initial bulk materials emphasis has been extended to include work on microwave devices and Josephson junctions, in addition to interest in the materials aspects of conductors. In Phase 2, ISTEC's structure will reflect these expanded activities: basic materials and physics research and the applications of bulk material, thin films, and wire or ribbon conductors. It was not stated how the budget will be divided between these latter three topics, and the impression was given that the two applied topics will be added through growth. From a number of sources, the panel learned that the focus of the electronics activities will be HTS junctions for SFQ circuits. The goal appears to be modest, a spread of 10% for 1 sigma in 5 years. Objectives for Ic, Rn, and circuit operating temperature were not stated. No system level goals were described. This author's view is that for a 5-year project at these funding levels, the goals could be much more aggressive.

It is not possible to describe here all the technical activities of ISTEC, but a summary follows of topics that were discussed in the presentations or during the laboratory tours.

Dr. Koshizuka presented a review of the ISTEC projects. One topic of particular interest for electronics is the successful growth of large single crystals (almost 1 in. diameter, with a goal of 2 in.) of YBCO. It was suggested that these would be useful as ground planes, and that film growth of YBCO on this homoepitaxial substrate is more perfect than on commonly used substrates. A superlattice of NBCO and PBCO on YBCO was grown to demonstrate the close lattice match with the substrate. The substrate can be doped to be insulating, if necessary. Although not stated specifically, it is also possible that a device technology in analogy with semiconductors is under consideration, with the devices made in the substrate rather than deposited on it.

Dr. Enomoto described the microwave and digital activities of Division 6 (Fundamental Technology for Device Applications). The staffing is 6 scientists on microwave, 5 on digital, and 8 on HTS junction development. A number of different junction approaches are being explored in a preliminary way, but none had progressed at the time of the WTEC visit to the point of good uniformity of Ic and Rn. Focused ion beams are being used for direct writing and also to prepare a damaged region or a narrow ridge in the substrate, which then nucleates a grain boundary (or possibly 3 boundaries) in the film. Two forms of a axis/c axis junctions are being made, one in Bi films in an in-plane geometry that uses the intrinsic junctions in the a-axis grain, the other using the boundary between c axis and a axis layers (grown sequentially on the single crystal YBCO).

Using ion beam damage junctions, a flip flop with 4 junctions has been demonstrated.

In the discussion of junction uniformity, the statement was made that ISTEC would like to be 2 years behind the targets of the U.S. "Big 3" (Conductus, Northrop Grumman, and TRW). Given that these U.S. targets are still far from the uniformity needed for circuits, this goal of ISTEC seems far too modest, particularly given their extensive analytical equipment.

A tour of the laboratories showed that ISTEC is extremely well equipped with characterization equipment of every description. The only limit on equipment seems to be space, not budgets. A microanalytical transmission electron microscope (TEM) was to be installed soon. This is an essential tool for the study of defects in HTS films, but such an instrument dedicated to HTS materials is beyond the dreams of any groups in the United States.

An introduction by Dr. Suzuki to the microwave (also at the "Western Consortium," or "Western Alliance" -- see the Matsushita and Sumitomo site reports) and mm-wave projects presented the market growth for wireless phones in Japan. The number of users is doubling each year, from 20 million at the end of 1996 to 40 million at the end of 1997. In 1998 the number of wireless phones is expected to exceed "stationary" phones (60 million). These numbers are surprising, in that only a few people can be seen using such phones on the subway or in the street.

The microwave and mm-wave projects are carried out at the Tamachi Laboratory, which the panel visited en-route to dinner. The space is rented from the Tokyo Gas Company, located near an area of extremely modern development (close to Haneda Airport) that is not fully occupied due to the end of the "bubble economy." The projects include the study of HTS filters and development of an integrated wide band antenna/Josephson junction mm-wave mixer. The 6 junctions in series, 1 µm apart in the mixer were made by ion damage of the substrate. This laboratory was notable for its exclusion of liquid nitrogen or helium for cooling, with all measurements being carried out only on cryocoolers of many various types, including pulse-tubes.

ISTEC is the largest laboratory engaged in superconductivity research, not only in Japan, but also in the world. Given that it will likely grow even further (in breadth of activities and in size) in Phase 2, it is discussed at length in Chapter 9 of this report.


Published: August 1998; WTEC Hyper-Librarian