Study on Fabrication Process of Single-Flux-Quantum Integrated Circiuts

2009 Fiscal Year Final Research Report

• Project/Area Number: 18080007
• Research Category: Grant-in-Aid for Scientific Research on Priority Areas
• Allocation Type: Single-year Grants
• Review Section: Science and Engineering
• Research Institution: Nagoya University
• Principal Investigator: AKIRA Fujimaki Nagoya University, 大学院・工学研究科, 教授 (20183931)
• Co-Investigator(Kenkyū-buntansha): HIROYUKI Akaike 名古屋大学, 大学院・工学研究科, 助教 (20273287)
• Project Period (FY): 2006 – 2009
• Keywords: 超伝導 / 単一磁束量子 / 局在電磁波 / ジョセフソン接合 / 窒化ニオブ

Research Abstract

We have studied Josephson junctions based on niobium nitride (NbN), which has 1.5 times larger superconducting energy gap than niobium. We have formed tunnel barriers by nitriding aluminum deposited on the base electrodes of NbN. These junctions show excellent reproducibility and controllability in quality parameters such as critical current density and characteristic voltage. We have also demonstrated intrinsically overdamped junctions by inserting normal conducting layers of NbNx. The junctions have high potential for high-speed operation in the single-flux-quantum logic circuit.

Research Products

• [Journal Article] 単一磁束量子回路による超高速信号処理 (2010)
  • Author(s): 藤巻朗
  • Journal Title: まぐね vol.5,No.1 Pages: 19-24
• [Journal Article] 単一磁束量子を用いた情報処理回路 (2010)
  • Author(s): 藤巻朗, 田中雅光
  • Journal Title: 電気学会誌 vol.130,No.3 Pages: 159-162
• [Journal Article] All MgB2 Josephson junctions with amorphous boron barriers (2010)
  • Author(s): N. Mitamura, C. Maruyama, H. Akaike, A. Fujimaki, R. Ishii, Y. Niihara, M. Naito
  • Journal Title: IEICE Trans. Electronics E93-C,No.4 Pages: 468-472
  • Peer Reviewed
• [Journal Article] The preparation process of plasma-nitrided barriers in NbN Josephson junctions for digital applications (2009)
  • Author(s): Y. Nagai, H. Akaike, R. Kanada, N. Naito, A. Fujimaki
  • Journal Title: Supercond. Sci. Technol. 22(11),No.114015 Pages: 5
  • Peer Reviewed
• [Journal Article] Current Resolution of a Single-Flux-Quantum Readout Circuit Based on Current-to-Time Conversion Toward a Flux Qubit System (2009)
  • Author(s): S. Nakamura, H. Numabe, A. Bozbey, A. Fujimaki
  • Journal Title: IEEE Trans. Appl. Supercond. 19(3) Pages: 973-976
  • Peer Reviewed
• [Journal Article] Single-Flux-Quantum Circuit Based Readout System for Detector Arrays by Using Time to Digital Conversion (2009)
  • Author(s): A. Bozbey, S. Miyajima, H. Akaike, A. Fujimaki
  • Journal Title: IEEE Trans. Appl. Supercond. 19(3) Pages: 509-513
  • Peer Reviewed
• [Journal Article] Self-Shunted NbN Junctions With NbNx/AlN Bilayered Barriers for 4 K Operation (2009)
  • Author(s): R. Kanada, Y. Nagai, H. Akaike, A. Fujimaki
  • Journal Title: IEEE Trans. Appl. Supercond. 19(3) Pages: 249-252
  • Peer Reviewed
• [Journal Article] Bit-Serial Single Flux Quantum Microprocessor CORE (2008)
  • Author(s): A. Fujimaki, M. Tanaka, T. Yamada, Y. Yamanashi, Heejoung Park, N. Yoshikawa
  • Journal Title: IEICE Trans. Electron. E91-C(3) Pages: 342-349
  • Peer Reviewed
• [Journal Article] Design and implementation of a pipelined 8 bit-serial single-flux-quantum microprocessor with cache memories (2007)
  • Author(s): M. Tanaka, Y. Yamanashi, N. Irie, H. -J. Park, S. Iwasaki, K. Takagi, K. Taketomi, A. Fujimaki, N. Yoshikawa, H. Terai, S. Yorozu
  • Journal Title: Supercond. Sci. Technol. 20(11) Pages: S305-S309
  • Peer Reviewed
• [Journal Article] Quantitative evaluation of delay time in the single-flux-quantum circuit (2007)
  • Author(s): S. Iwasaki, M. Tanaka, N. Irie, A. Fujimaki, N. Yoshikawa, H. Terai, S. Yorozu
  • Journal Title: Physica C 463-465 Pages: 1068-1071
  • Peer Reviewed
• [Journal Article] Effects of surface morphologies of base electrodes on the qualities of Nb/AlOx/Nb Josephson junctions with high critical densities (2007)
  • Author(s): N.J. Mehta, N. Mitamura, R. Kanada, H. Akaike, A. Fujimaki
  • Journal Title: Physica C 463-465 Pages: 975-978
  • Peer Reviewed
• [Journal Article] A New Design Approach for High-Throughput Arithmetic Circuits for Single-Flux-Quantum Microprocessors (2007)
  • Author(s): M. Tanaka, Y. Yamanashi, Y. Kamiya, A. Akimoto, N. Irie, H. -J. Park, A. Fujimaki, N. Yoshikawa, H. Terai, S. Yorozu
  • Journal Title: IEEE Trans. Appl. Supercond. 17(2) Pages: 516-519
  • Peer Reviewed
• [Presentation] NbN Josephson junctions for SFQ LSIs (2010)
  • Author(s): A. Fujimaki, Y. Nagai, N. Naito, H. Akaike
  • Organizer: The 3rd Superconducting SFQ VLSI Workshop (SSV 2010) A01-1
  • Place of Presentation: Yokohama, Japan
  • Year and Date: 2010-01-13
• [Presentation] Fabrication of NbN Josephson Junctions with Plasma- Nitrided AlN Barriers Formed by RF Substrate Biasing (2010)
  • Author(s): Y. Nagai, N. Naito, H. Akaike, A. Fujimaki
  • Organizer: The 3rd Superconducting SFQ VLSI Workshop (SSV 2010) P15
  • Place of Presentation: Yokohama, Japan
  • Year and Date: 2010-01-13
• [Presentation] Development of Single-Flux-Quantum Circuits for a Compact Neutron Diffractometer (2009)
  • Author(s): A. Fujimaki, I. Nakanishi, S. Miyajima, T. Ishida
  • Organizer: The 5th East Asia Symposium on Superconductor Electronics (EASSE2009) M2-2
  • Place of Presentation: Nanjing, China
  • Year and Date: 20091012-20091015
• [Presentation] RSFQ Circuit Design for Detector Applications (2009)
  • Author(s): A. Fujimaki
  • Organizer: 6th FLUXONICS RSFQ design workshop
  • Place of Presentation: Ilmenau, Germany
  • Year and Date: 20090726-20090729
• [Presentation] Preparation Process of Plasma-Nitrided Barriers in NbN Josephson Junctions for Digital Applications (2009)
  • Author(s): Y. Nagai, R. Kanada, H. Akaike, A. Fujimaki
  • Organizer: 12th Int. Superconductive Electronics Conf. (ISEC2009) TD-O6 Extended Abstracts of the 12th International Superconductive Electronics Conference TD-O6
  • Place of Presentation: Fukuoka, Japan
  • Year and Date: 20090616-20090619
• [Presentation] Preparation of MgB2/B/MgB2 Josephson Junctions (2009)
  • Author(s): N. Mitamura, C. Maruyama, H. Akaike, A. Fujimaki, R. Inoue, Y. Niihara, M. Naito
  • Organizer: 12th Int. Superconductive Electronics Conf. (ISEC2009) TD-P14Extended Abstracts of the 12th International Superconductive Electronics Conference TD-P14
  • Place of Presentation: Fukuoka, Japan
  • Year and Date: 20090616-20090619
• [Presentation] Demonstration of 2x3 Reconfigurable-Data-Path Processors with 14000 Josephson Junctions (2009)
  • Author(s): A. Fujimaki, R. Kasagi, K. Takagi, I. Kataeva, H. Akaike, M. Tanaka, N. Takagi, N. Yoshikawa, K. Murakami
  • Organizer: 12th Int. Superconductive Electronics Conf. (ISEC2009) (SSV Session) SP-O4Extended Abstracts of the 12th International Superconductive Electronics Conference SP-O4
  • Place of Presentation: Fukuoka, Japan
  • Year and Date: 20090616-20090619
• [Presentation] Electrical Properties of All MgB2 Josephson Junctions with Different Tunnel Barriers (2009)
  • Author(s): N. Mitamura, C. Maruyama, H. Akaike, A. Fujimaki, R. Ishii, Y. Niihara, M. Naito
  • Organizer: The 2nd Superconducting SFQ VLSI Workshop (SSV2009) O10
  • Place of Presentation: Fukuoka, Japan
  • Year and Date: 20090615-20090617
• [Presentation] Recent Progress in Superconducting Digital Electronics (2009)
  • Author(s): A. Fujimaki
  • Organizer: Joint JSPS-ESF International Conference on Nanoscience and Engineering in Superconductivity
  • Place of Presentation: Tsukuba, Japan
  • Year and Date: 20090323-20090326
• [Presentation] Self-shunted NbN junctions with NbNx/AlN/NbNx multilayered barriers for 4 K operation (2008)
  • Author(s): R. Kanada, Y. Nagai, H. Akaike, A. Fujimaki
  • Organizer: 2008 Appl. Supercond. Conf. (ASC2008) 2EPH01
  • Place of Presentation: Chicago, Illinois, USA
  • Year and Date: 20080817-20080822
• [Presentation] Fabrication and measurement of high quality and high critical current density Nb/AlOx/Nb Josephson junction (2008)
  • Author(s): N. Mitamura, H. Akaike, A. Fujimaki
  • Organizer: Superconducting SFQ VLSI Workshop (SSV2008) P1-3
  • Place of Presentation: Yokohama, Japan
  • Year and Date: 2008-03-17
• [Presentation] Self-shunted NbN Josephson Junctions with AlN/NbNx Barriers (2008)
  • Author(s): A. Fujimaki, R. Kanada, Y. Nagai, H. Akaike
  • Organizer: Superconducting SFQ VLSI Workshop (SSV2008) A1-2
  • Place of Presentation: Yokohama, Japan
  • Year and Date: 2008-03-17
• [Presentation] Superconducting Elecronics in Japan (2007)
  • Author(s): A. Fujimaki
  • Organizer: The 15th Biennial Workshop on Superconductive Electronics: Devices, Circuits and Systems
  • Place of Presentation: Lakeville, Connecticut, USA
  • Year and Date: 20071014-20071018
• [Presentation] Recent Progress in SFQ LSI Technology (2007)
  • Author(s): A. Fujimaki
  • Organizer: 8th European Conf. on Applied Superconductivity (EUCAS2007)
  • Place of Presentation: Brussels, Belgium
  • Year and Date: 20070916-20070920
• [Presentation] Development of High-Speed Single-Flux-Quantum Microprocessors (2006)
  • Author(s): A. Fujimaki, M. Tanaka, N. Irie, S. Iwasaki, T. Yamada, N. Takagi, H. Park, Y. Yamanashi, N. Yoshikawa, H. Terai, S. Yorozu, Y. Takai
  • Organizer: 19th Int. Symposium on Superconductivity (ISS2006) FD-22-INV
  • Place of Presentation: Nagoya, Japan
  • Year and Date: 20061030-20061101
• [Presentation] High resolution analog-to-digital converter toward a multiple detectors system (2006)
  • Author(s): A. Fujimaki, A. Sekiya, Y. Nishido, T. Yamazaki, H. Sato, H.M. Shimizu
  • Organizer: 2006 Appl. Supercond. Conf. (ASC2006) 2EX06
  • Place of Presentation: Seattle, Washington, USA
  • Year and Date: 20060827-20060901
• [Presentation] Recent Progress in Rapid-single-flux-quantum Circuits (2006)
  • Author(s): A. Fujimaki
  • Organizer: 11th Int. Conferences on Modern Materials and Technologies (CIMTEC2006) (11th Int. Ceramics Congress and 4th Forum on New Materials) IC-II. 5: SL04
  • Place of Presentation: Sicily, Italy
  • Year and Date: 20060604-20060609
• [Book] 第24章SFQ回路とその情報通信機器応用"超電導の応用最新技術 (2008)
  • Author(s): 藤巻朗, 日高睦夫
  • Total Pages: 277-292
  • Publisher: シーエムシー出版
• [Book] "第6章3超伝導集積回路"テラヘルツ技術総覧(廣本宣久) (2007)
  • Author(s): 藤巻朗
  • Total Pages: 376-388
  • Publisher: 有限会社エヌジーティー