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Kim SH, Braun TM, Lee HJ, Moffat TP, Josell D. Microstructure and Texture in Copper Filled Millimeter Scale Through Silicon Vias. JOURNAL OF THE ELECTROCHEMICAL SOCIETY 2022; 169:10.1149/1945-7111/ac5ad8. [PMID: 36936546 PMCID: PMC10020947 DOI: 10.1149/1945-7111/ac5ad8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
The microstructure and crystallographic texture of copper electrodeposits in millimeter scale through silicon vias are characterized using electron backscatter diffraction. The deposits obtained from additive-containing CuSO4-H2SO4 electrolytes are characteristic of the superconformal deposition process, with growth textures and columnar grains consistent with previous findings in smaller TSV. The microstructure, like the filling evolution it records, changes substantially with chloride concentration for the concentrations of polymer suppressor used. With chloride concentrations of 80 μmol·L-1 and less, columnar grains of Cu capture the linear motion of the local growth front during filling with a strong <110> orientation along the elongated grain axes typical of deposition in chloride-containing Cu electrolytes. In the mid- and upper- via locations these columnar grains are angled upward from the sidewalls toward the center of the v-shaped growth front. In a limited region adjacent to the via bottom they extend vertically from the bottom surface. With millimolar chloride concentration, deposition also exhibits columnar grains with preferred <110> growth orientation in the lower region of the via and adjacent to the sidewalls. However, separation of the central deposit from the sidewalls results in a convex geometry of the growth front and spatially varying texture in most of the deposit.
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Affiliation(s)
- S-H Kim
- Department of Materials Science and Engineering, Dong-A University, Saha-Gu, Busan 49315 Korea
| | - T M Braun
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 USA
| | - H-J Lee
- Department of Materials Science and Engineering, Dong-A University, Saha-Gu, Busan 49315 Korea
| | - T P Moffat
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 USA
| | - D Josell
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 USA
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McKay KS, Hite DA, Kent PD, Kotler S, Leibfried D, Slichter DH, Wilson AC, Pappas DP. Measurement of electric-field noise from interchangeable samples with a trapped-ion sensor. PHYSICAL REVIEW. A 2021; 104:052610. [PMID: 38915757 PMCID: PMC11194989 DOI: 10.1103/physreva.104.052610] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
We demonstrate the use of a single trapped ion as a sensor to probe electric-field noise from interchangeable test surfaces. As proof of principle, we measure the magnitude and distance dependence of electric-field noise from two ion-trap-like samples with patterned Au electrodes. This trapped-ion sensor could be combined with other surface characterization tools to help elucidate the mechanisms that give rise to electric-field noise from ion-trap surfaces. Such noise presents a significant hurdle for performing large-scale trapped-ion quantum computations.
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Affiliation(s)
- Kyle S. McKay
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Dustin A. Hite
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
| | - Philip D. Kent
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Shlomi Kotler
- Department of Applied Physics, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Dietrich Leibfried
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
| | - Daniel H. Slichter
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
| | - Andrew C. Wilson
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
| | - David P. Pappas
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
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Hite DA, McKay KS, Pappas DP. Surface science motivated by heating of trapped ions from the quantum ground state. NEW JOURNAL OF PHYSICS 2021; 23:10.1088/1367-2630/ac2c2c. [PMID: 38487593 PMCID: PMC10938442 DOI: 10.1088/1367-2630/ac2c2c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 03/17/2024]
Abstract
For the past two and a half decades, anomalous heating of trapped ions from nearby electrode surfaces has continued to demonstrate unexpected results. Caused by electric-field noise, this heating of the ions' motional modes remains an obstacle for scalable quantum computation with trapped ions. One of the anomalous features of this electric-field noise is the reported nonmonotonic behavior in the heating rate when a trap is incrementally cleaned by ion bombardment. Motivated by this result, the present work reports on a surface analysis of a sample ion-trap electrode treated similarly with incremental doses of Ar+ ion bombardment. Kelvin probe force microscopy and x-ray photoelectron spectroscopy were used to investigate how the work functions on the electrode surface vary depending on the residual contaminant coverage between each treatment. It is shown that the as-fabricated Au electrode is covered with a hydrocarbon film that is modified after the first treatment, resulting in work functions and core-level binding energies that resemble that of atomic-like carbon on Au. Changes in the spatial distribution of work functions with each treatment, combined with a suggested phenomenological coverage and surface-potential roughness dependence to the heating, appear to be related to the nonmonotonic behavior previously reported.
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Affiliation(s)
- D A Hite
- National Institute of Standards and Technology, Boulder, Colorado 80305, United States of America
| | - K S McKay
- National Institute of Standards and Technology, Boulder, Colorado 80305, United States of America
- Department of Physics, University of Colorado, Boulder, Colorado 80309, United States of America
| | - D P Pappas
- National Institute of Standards and Technology, Boulder, Colorado 80305, United States of America
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Shim YP, Ruskov R, Hurst HM, Tahan C. Induced quantum dot probe for material characterization. APPLIED PHYSICS LETTERS 2019; 114:10.1063/1.5053756. [PMID: 38618628 PMCID: PMC11010771 DOI: 10.1063/1.5053756] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
We propose a non-destructive means of characterizing a semiconductor wafer via measuring parameters of an induced quantum dot on the material system of interest with a separate probe chip that can also house the measurement circuitry. We show that a single wire can create the dot, determine if an electron is present, and be used to measure critical device parameters. Adding more wires enables more complicated (potentially multi-dot) systems and measurements. As one application for this concept we consider silicon metal-oxide-semiconductor (MOS) and silicon/silicon-germanium quantum dot qubits relevant to quantum computing and show how to measure low-lying excited states (so-called "valley" states). This approach provides an alternative method for characterization of parameters that are critical for various semiconductor-based quantum dot devices without fabricating such devices.
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Affiliation(s)
- Yun-Pil Shim
- Laboratory for Physical Sciences, College Park, Maryland 20740, USA
- Department of Physics, University of Maryland, College Park, Maryland 20742, USA
| | - Rusko Ruskov
- Laboratory for Physical Sciences, College Park, Maryland 20740, USA
- Department of Physics, University of Maryland, College Park, Maryland 20742, USA
| | - Hilary M. Hurst
- Laboratory for Physical Sciences, College Park, Maryland 20740, USA
| | - Charles Tahan
- Laboratory for Physical Sciences, College Park, Maryland 20740, USA
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Boldin IA, Kraft A, Wunderlich C. Measuring Anomalous Heating in a Planar Ion Trap with Variable Ion-Surface Separation. PHYSICAL REVIEW LETTERS 2018; 120:023201. [PMID: 29376708 DOI: 10.1103/physrevlett.120.023201] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Indexed: 06/07/2023]
Abstract
Cold ions trapped in the vicinity of conductive surfaces experience heating of their oscillatory motion. Typically, the rate of this heating is orders of magnitude larger than expected from electric field fluctuations due to thermal motion of electrons in the conductors. This effect, known as anomalous heating, is not fully understood. One of the open questions is the heating rate's dependence on the ion-electrode separation. We present a direct measurement of this dependence in an ion trap of simple planar geometry. The heating rates are determined by taking images of a single ^{172}Yb^{+} ion's resonance fluorescence after a variable heating time and deducing the trapped ion's temperature from measuring its average oscillation amplitude. Assuming a power law for the heating rate versus ion-surface separation dependence, an exponent of -3.79±0.12 is measured.
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Affiliation(s)
- Ivan A Boldin
- Department Physik, Naturwissenschäftlich-Technische Fakultät, Universität Siegen, 57068 Siegen, Germany
| | - Alexander Kraft
- Department Physik, Naturwissenschäftlich-Technische Fakultät, Universität Siegen, 57068 Siegen, Germany
| | - Christof Wunderlich
- Department Physik, Naturwissenschäftlich-Technische Fakultät, Universität Siegen, 57068 Siegen, Germany
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Hite DA, McKay KS, Kotler S, Leibfried D, Wineland DJ, Pappas DP. Measurements of trapped-ion heating rates with exchangeable surfaces in close proximity. ACTA ACUST UNITED AC 2017. [DOI: 10.1557/adv.2017.14] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Baumgart I, Cai JM, Retzker A, Plenio MB, Wunderlich C. Ultrasensitive Magnetometer using a Single Atom. PHYSICAL REVIEW LETTERS 2016; 116:240801. [PMID: 27367376 DOI: 10.1103/physrevlett.116.240801] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Indexed: 06/06/2023]
Abstract
Precision sensing, and in particular high precision magnetometry, is a central goal of research into quantum technologies. For magnetometers, often trade-offs exist between sensitivity, spatial resolution, and frequency range. The precision, and thus the sensitivity of magnetometry, scales as 1/sqrt[T_{2}] with the phase coherence time T_{2} of the sensing system playing the role of a key determinant. Adapting a dynamical decoupling scheme that allows for extending T_{2} by orders of magnitude and merging it with a magnetic sensing protocol, we achieve a measurement sensitivity even for high frequency fields close to the standard quantum limit. Using a single atomic ion as a sensor, we experimentally attain a sensitivity of 4.6 pT/sqrt[Hz] for an alternating-current magnetic field near 14 MHz. Based on the principle demonstrated here, this unprecedented sensitivity combined with spatial resolution in the nanometer range and tunability from direct current to the gigahertz range could be used for magnetic imaging in as of yet inaccessible parameter regimes.
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Affiliation(s)
- I Baumgart
- Department Physik, Naturwissenschaftlich-Technische Fakultät, Universität Siegen, 57068 Siegen, Germany
| | - J-M Cai
- School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
| | - A Retzker
- Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem 91904, Givat Ram, Israel
| | - M B Plenio
- Institut für Theoretische Physik, Universität Ulm, 89069 Ulm, Germany
| | - Ch Wunderlich
- Department Physik, Naturwissenschaftlich-Technische Fakultät, Universität Siegen, 57068 Siegen, Germany
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