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edfas.org 55 ELECTRONIC DEVICE FAILURE ANALYSIS | VOLUME 21 NO. 2 separated by interlayer SiO 2 , vias, and junctions), defects such as shorts and resistive contacts should be sensitive to changes in temperature induced by the scanning laser beam and allow the detection of localized TIVA signals in biased circuits. In fact, a short between Nb layers in a register file was located using TIVA and imaged using FIB cross-sectioning and scanning electron microscopy (SEM). [7] The image on the right in the figure above shows an example of three isolated TIVA signals (dark circles) obtained on a biased decoder circuit scannedwith a 1064 nm laser, with the reflected light image on the left. These areas contain Nb traces, JJs, and vias, and are currently undergoing FIB/SEM analysis to determine the nature of the isolated defects producing the TIVA signals. Superconducting electronics are highly unlikely to become as pervasive as CMOS, but they may play an important role in beyond-exascale classical high-perfor- mance computers, wherehigh speedandenergy efficiency are required. In addition, applications such as quantum computing and quantum information science, where certain types of qubits operate at cryogenic temperatures, may benefit from using superconducting circuits as an interface between the cryogenic environment and the real world. A growing interest in this area, demonstrated by efforts at a variety of companies (e.g., IBM, Google, and Intel) and targetedgovernment investments (e.g., National Quantum Initiative, U.S.; Quantum Flagship Initiative, EU; and National Laboratory for Quantum Information Science, China) suggest that the adaptation and devel- opment of new failure analysis and reliability tools will be needed to enable the advances required for the next generation of computation. ACKNOWLEDGMENTS Sandia National Laboratories, amulti-mission labora- tory managed and operated by National Technology and Engineering Solutions of Sandia LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525. This column describes objective technical results and analysis. Any subjective views or opinions that might be expressed in the column do not necessarily represent the views of the U.S. Department of Energy or the United States government. REFERENCES 1. exascaleproject.org. 2. iarpa.gov/index.php/research-programs/c3. 3. irds.ieee.org . 4. S.K. Tolpygo, V. Bolkhovsky, T.J. Weir, A. Wynn, D.E. Oates, and L.M. Johnson: IEEE Trans. Appl. Supercond., 2016, 26 (3), p. 1100110. 5. V.K. Semenov, Y.A. Polyakov, and S.K. Tolpygo: “AC-Biased Shift Registers as Fabrication Process Benchmark Circuits and Flux Trapping Diagnostic Tool,” IEEE Trans. Appl. Supercond., 2017, 27 (4), p. 1301409. 6. N. Missert, P.G. Kotula, M. Rye, L. Rehm, V. Sluka, A.D. Kent, D. Yohannes, A.F. Kirichenko, I.V. Vernik, O.A. Mukhanov, V. Bolkhov- sky, A. Wynn, L. Johnson, andM. Gouker, IEEE Trans. Appl. Supercond., 2017, 27 (4), p. 1100704. 7. M.W. Jenkins, P. Tangyunyong, N.A. Missert, I. Vernik, A. Kirichhenko, O. Mukhanov, A. Wynn, V. Bolkhovsky, and L. Johnson: Proc. 44th Int. Symp. Test. Fail. Anal. (ISTFA), 2018. p. 148. ABOUT THE AUTHOR Nancy Missert earned her Ph.D. in physics at Stanford University where she focused on 2D supercon- ductors. She was a member of the High-Temperature Superconducting Electronics Team at the National Institute of Standards and Technol- ogy in Boulder, Colo., prior to becoming a principal member of the technical staff at Sandia National Lab- oratories. Missert recently led the yield risk mitigation effort as part of the IARPA C3 program. Her research inter- ests include understanding defects in superconductors, oxides, semiconductors, and magnetic materials. Reflected light image (left) and TIVA image (right) of a biased decoder at ambient temperature using a 1064 nm laser. Three distinct signals (dark circles) were detected with TIVA.