Custom designed superconducting devices beat out the competition for certain specialized applications
While superconductivity has never made it as a mainstraem technology for computer applications, it has excelled for magnetic detectors, certain low-noise amplifiers and and other low level of integration applications.
Dr. Ketchen worked in design and test in the original IBM effort to build a superconducting computer circa 1980 and was a pioneer in the design, fabrication and characterization of planar dc SQUID devices from the mid 1970’s through the mid 1990’s. This included the invention and development of the now industry standard “washer” SQUID with spiral input coil and integrated miniature susceptometers and magnetometers used with colleagues in a host of ground-breaking physics experiments, including the discovery of half-integral flux quantization in high Tc superconductors. Building on his experience in process integration and running the silicon fab line at IBM Research he developed a deep submicron Josephson technology featuring planarization and self-aligned contacts for analog and digital devices. He co-advised an ISSCC award winning Ph.D. project on superconducting A to D converters and over the past several years has worked on superconducting qubits for quantum computing, including launching and serving as principal investigator of a large multi-institutional government (IARPA) sponsored project on coupled qubits in both 2D and 3D implementations.
1. High-coherence hybrid superconducting qubit
Steffen M, Kumar S, DiVincenzo DP, Rozen JR, Keefe GA, Rothwell MB, Ketchen MB (2010). Phys Rev Lett 105,100502
2. Superconducting bandpass delta-sigma modulator with 2.23-GHz center frequency and 42.6-GHz sampling rate
Bulzacchelli JF, Lee HS, Misewich JA, Ketchen MB (2002). IEEE J of Solid-State Circuits 37: 1695-1702
Best student paper award as presented at 2002 IEEE international solid state circuits conference, ISSCC
3. Sub-um planarized Nb-AlOx-Nb Josephson junction process for 125 mm wafers developed in partnership with Si technology
Ketchen MB, Pearson DJ, Kleinsasser AW, Hu C-K, Smyth M, Logan J, Stawiasz K, Baran E, Jaso M, Ross T, Petrillo K, Manny M, Basavaiah S, Brodsky S, Kaplan SB, Gallagher WJ, Bhushan M (1991). Appl Phys Lett 59:2609-2611
4. The Josephson cross sectional model experiment
Ketchen MB, Herrell DJ, Anderson CJ (1985) T J. Appl Phys 57: 2550-2574
5. Miniature SQUID susceptometer
Ketchen MB, Kopley T, Ling H (1984). Appl Phys Lett 44: 1008-1010
6. Ultra-low-noise tunnel junction dc SQUID with a tightly coupled planar input coil
Ketchen MB, Jaycox JM (1982). Appl Phys Lett 40: 736-738