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Gu S, Kimura Y, Yan X, Liu C, Cui Y, Ju Y, Toku Y. Micromachined structures decoupling Joule heating and electron wind force. Nat Commun 2024; 15:6044. [PMID: 39025893 PMCID: PMC11258259 DOI: 10.1038/s41467-024-50351-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Accepted: 07/09/2024] [Indexed: 07/20/2024] Open
Abstract
Microstructural changes in conductive materials induced by electric current treatments, such as electromigration and electroplasticity, are critical in semiconductor and metal processing. However, owing to the inevitable thermal effect (Joule heating), the athermal effect on microstructural modifications remains obscure. This paper presents an approach of utilizing pre-micromachined structures, which obstruct current flow but maintain a thermal history similar to that of the matrix, effectively disentangling the thermal and athermal effects. A duplex stainless-steel material is selected to validate the feasibility of this method. Microstructural characterizations show that the athermal effect, especially the electron wind force (EWF), primarily governs the element diffusion and phase transformation in this study. Moreover, many σ phases (Cr-enriched) are precipitated in the micromachined structures, whereas no precipitation occurred in the matrix, suggesting that the directional EWF disrupts the Cr aggregation caused by Joule heating. Furthermore, we present a critical formula for determining the dimensions of micromachined structures of commonly used metallic materials. The proposed method may serve as an effective and powerful tool for unveiling the athermal effect on microstructural alterations.
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Affiliation(s)
- Shaojie Gu
- Department of Micro-Nano Mechanical Science and Engineering, Graduate School of Engineering, Nagoya University, Nagoya, 464-8601, Japan.
| | - Yasuhiro Kimura
- Department of Micro-Nano Mechanical Science and Engineering, Graduate School of Engineering, Nagoya University, Nagoya, 464-8601, Japan
| | - Xinming Yan
- Department of Micro-Nano Mechanical Science and Engineering, Graduate School of Engineering, Nagoya University, Nagoya, 464-8601, Japan
| | - Chang Liu
- Department of Micro-Nano Mechanical Science and Engineering, Graduate School of Engineering, Nagoya University, Nagoya, 464-8601, Japan
| | - Yi Cui
- Department of Mechanical Systems Engineering, Graduate School of Engineering, Nagoya University, Nagoya, 464-8601, Japan
| | - Yang Ju
- State Key Laboratory of Fluid Power and Mechatronic Systems, School of Mechanical Engineering, Zhejiang University, Hangzhou, 310030, China.
| | - Yuhki Toku
- Department of Micro-Nano Mechanical Science and Engineering, Graduate School of Engineering, Nagoya University, Nagoya, 464-8601, Japan.
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2
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Li X, Zhu Q, Hong Y, Zheng H, Wang J, Wang J, Zhang Z. Revealing the pulse-induced electroplasticity by decoupling electron wind force. Nat Commun 2022; 13:6503. [PMID: 36316328 PMCID: PMC9622885 DOI: 10.1038/s41467-022-34333-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 10/21/2022] [Indexed: 11/26/2022] Open
Abstract
Micro/nano electromechanical systems and nanodevices often suffer from degradation under electrical pulse. However, the origin of pulse-induced degradation remains an open question. Herein, we investigate the defect dynamics in Au nanocrystals under pulse conditions. By decoupling the electron wind force via a properly-designed in situ TEM electropulsing experiment, we reveal a non-directional migration of Σ3{112} incoherent twin boundary upon electropulsing, in contrast to the expected directional migration under electron wind force. Quantitative analyses demonstrate that such exceptional incoherent twin boundary migration is governed by the electron-dislocation interaction that enhances the atom vibration at dislocation cores, rather than driven by the electron wind force in classic model. Our observations provide valuable insights into the origin of electroplasticity in metallic materials at the atomic level, which are of scientific and technological significances to understanding the electromigration and resultant electrical damage/failure in micro/nano-electronic devices.
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Affiliation(s)
- Xing Li
- grid.13402.340000 0004 1759 700XCenter of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027 China
| | - Qi Zhu
- grid.13402.340000 0004 1759 700XCenter of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027 China
| | - Youran Hong
- grid.13402.340000 0004 1759 700XCenter of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027 China
| | - He Zheng
- grid.49470.3e0000 0001 2331 6153School of Physics and Technology, Center for Electron Microscopy, MOE Key Laboratory of Artificial Micro- and Nano-structures, and Institute for Advanced Studies, Wuhan University, Wuhan, 430072 China
| | - Jian Wang
- grid.24434.350000 0004 1937 0060Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE 68583 USA
| | - Jiangwei Wang
- grid.13402.340000 0004 1759 700XCenter of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027 China ,grid.13402.340000 0004 1759 700XWenzhou Key Laboratory of Novel Optoelectronic and Nano Materials, Institute of Wenzhou, Zhejiang University, Wenzhou, 325006 China
| | - Ze Zhang
- grid.13402.340000 0004 1759 700XCenter of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027 China
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3
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Boccardo F, Pierre-Louis O. Controlling the Shape of Small Clusters with and without Macroscopic Fields. PHYSICAL REVIEW LETTERS 2022; 128:256102. [PMID: 35802436 DOI: 10.1103/physrevlett.128.256102] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 05/09/2022] [Indexed: 06/15/2023]
Abstract
Despite major advances in the understanding of the formation and dynamics of nanoclusters in the past decades, theoretical bases for the control of their shape are still lacking. We investigate strategies for driving fluctuating few-particle clusters to an arbitrary target shape in minimum time with or without an external field. This question is recast into a first passage problem, solved numerically, and discussed within a high temperature expansion. Without field, large-enough low-energy target shapes exhibit an optimal temperature at which they are reached in minimum time. We then compute the optimal way to set an external field to minimize the time to reach the target, leading to a gain of time that grows when increasing cluster size or decreasing temperature. This gain can shift the optimal temperature or even create one. Our results could apply to clusters of atoms at equilibrium, and colloidal or nanoparticle clusters under thermo- or electrophoresis.
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Affiliation(s)
- Francesco Boccardo
- Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, 69622 Villeurbanne, France
| | - Olivier Pierre-Louis
- Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, 69622 Villeurbanne, France
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4
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Catalyst-free synthesis of sub-5 nm silicon nanowire arrays with massive lattice contraction and wide bandgap. Nat Commun 2022; 13:3467. [PMID: 35725850 PMCID: PMC9209539 DOI: 10.1038/s41467-022-31174-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 05/29/2022] [Indexed: 11/08/2022] Open
Abstract
The need for miniaturized and high-performance devices has attracted enormous attention to the development of quantum silicon nanowires. However, the preparation of abundant quantities of silicon nanowires with the effective quantum-confined dimension remains challenging. Here, we prepare highly dense and vertically aligned sub-5 nm silicon nanowires with length/diameter aspect ratios greater than 10,000 by developing a catalyst-free chemical vapor etching process. We observe an unusual lattice reduction of up to 20% within ultra-narrow silicon nanowires and good oxidation stability in air compared to conventional silicon. Moreover, the material exhibits a direct optical bandgap of 4.16 eV and quasi-particle bandgap of 4.75 eV with the large exciton binding energy of 0.59 eV, indicating the significant phonon and electronic confinement. The results may provide an opportunity to investigate the chemistry and physics of highly confined silicon quantum nanostructures and may explore their potential uses in nanoelectronics, optoelectronics, and energy systems.
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5
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Dvornichenko AV, Kharchenko VO, Kharchenko DO. Electromigration-induced formation of percolating adsorbate islands during condensation from the gaseous phase: a computational study. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2021; 12:694-703. [PMID: 34354898 PMCID: PMC8290097 DOI: 10.3762/bjnano.12.55] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 06/25/2021] [Indexed: 06/13/2023]
Abstract
We provide a computational study of a change in the morphology of a growing thin film during condensation caused by electromigration effects. It will be shown, that separated circular adsorbate islands, realized in an isotropic system, become elongated in the direction of the applied electrical field. We discuss the dependence of the critical value of the strength of the applied electrical field, responsible for the formation of percolating adsorbate islands, on main control parameters. This study provides insight into details of electromigration effects during the self-organization of adatoms into percolating adsorbate islands during condensation from the gaseous phase. We will show that the elongated morphology of adsorbate islands remains stable if the electric field is turned off.
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Affiliation(s)
| | - Vasyl O Kharchenko
- Institute of Applied Physics, National Academy of Sciences of Ukraine, 58 Petropavlivska St., 40000 Sumy, Ukraine
| | - Dmitrii O Kharchenko
- Institute of Applied Physics, National Academy of Sciences of Ukraine, 58 Petropavlivska St., 40000 Sumy, Ukraine
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6
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Leroy F, El Barraj A, Cheynis F, Müller P, Curiotto S. Atomic Transport in Au-Ge Droplets: Brownian and Electromigration Dynamics. PHYSICAL REVIEW LETTERS 2019; 123:176101. [PMID: 31702228 DOI: 10.1103/physrevlett.123.176101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Indexed: 06/10/2023]
Abstract
The deposition of Au on Ge(111)-sqrt[3]×sqrt[3]-Au above the eutectic temperature results in the formation of AuGe liquid droplets that reach the liquidus composition by digging a hole in the Ge substrate. The combination of low-energy electron microscopy and atomic force microscopy measurements shows that AuGe droplets randomly migrate or electromigrate under an applied electric current dragging their underneath hole. The droplet motion is due to a mass transport phenomenon based on Ge dissolution at the droplet front and Ge crystallization at its rear. At high temperature the mass transport is limited by attachment or detachment at the solid-liquid interface and the activation energy is 1.05±0.3 eV. At low temperature the effective activation energy increases as a function of the droplet radius. This behavior is attributed to the nucleation of 2D layers at the faceted liquid-solid interface.
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Affiliation(s)
- F Leroy
- Aix Marseille Univ, CNRS, CINAM, Marseille, France
| | - A El Barraj
- Aix Marseille Univ, CNRS, CINAM, Marseille, France
| | - F Cheynis
- Aix Marseille Univ, CNRS, CINAM, Marseille, France
| | - P Müller
- Aix Marseille Univ, CNRS, CINAM, Marseille, France
| | - S Curiotto
- Aix Marseille Univ, CNRS, CINAM, Marseille, France
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7
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Imaging Atomic Scale Dynamics on III-V Nanowire Surfaces During Electrical Operation. Sci Rep 2017; 7:12790. [PMID: 28986546 PMCID: PMC5630597 DOI: 10.1038/s41598-017-13007-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 09/12/2017] [Indexed: 11/08/2022] Open
Abstract
As semiconductor electronics keep shrinking, functionality depends on individual atomic scale surface and interface features that may change as voltages are applied. In this work we demonstrate a novel device platform that allows scanning tunneling microscopy (STM) imaging with atomic scale resolution across a device simultaneously with full electrical operation. The platform presents a significant step forward as it allows STM to be performed everywhere on the device surface and high temperature processing in reactive gases of the complete device. We demonstrate the new method through proof of principle measurements on both InAs and GaAs nanowire devices with variable biases up to 4 V. On InAs nanowires we observe a surprising removal of atomic defects and smoothing of the surface morphology under applied bias, in contrast to the expected increase in defects and electromigration-related failure. As we use only standard fabrication and scanning instrumentation our concept is widely applicable and opens up the possibility of fundamental investigations of device surface reliability as well as new electronic functionality based on restructuring during operation.
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8
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Wang N, Bevan KH, Provatas N. Phase-Field-Crystal Model for Electromigration in Metal Interconnects. PHYSICAL REVIEW LETTERS 2016; 117:155901. [PMID: 27768372 DOI: 10.1103/physrevlett.117.155901] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Indexed: 05/11/2023]
Abstract
We propose an atomistic model of electromigration (EM) in metals based on a recently developed phase-field-crystal (PFC) technique. By coupling the PFC model's atomic density field with an applied electric field through the EM effective charge parameter, EM is successfully captured on diffusive time scales. Our framework reproduces the well-established EM phenomena known as Black's equation and the Blech effect, and also naturally captures commonly observed phenomena such as void nucleation and migration in bulk crystals. A resistivity dipole field arising from electron scattering on void surfaces is shown to contribute significantly to void migration velocity. With an intrinsic time scale set by atomic diffusion rather than atomic oscillations or hopping events, as in conventional atomistic methods, our theoretical approach makes it possible to investigate EM-induced circuit failure at atomic spatial resolution and experimentally relevant time scales.
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Affiliation(s)
- Nan Wang
- Department of Physics, McGill University, Montreal, Québec H3A 2T8, Canada
| | - Kirk H Bevan
- Materials Engineering, McGill University, Montreal, Québec H3A 2T8, Canada
| | - Nikolas Provatas
- Department of Physics, McGill University, Montreal, Québec H3A 2T8, Canada
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9
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Yan K, Yao W, Yang L, Cao J, Zhao Y, Zhao L, Zhu Y. The formation of heterointerface defects in Au/Cu films on Si substrates under direct current in a vacuum ultraviolet environment. Phys Chem Chem Phys 2016; 18:4019-25. [PMID: 26778294 DOI: 10.1039/c5cp06499f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Au/Cu metallic films were deposited on p-Si(100) substrates with and without an Au upper layer by magnetron sputtering. The defect formation and nanoscale interfacial evolution at the Au/Cu and Cu/Si interfaces were studied by using Auger electron spectroscopy (AES) and high resolution transmission electron microscopy (HRTEM). The results showed that an increase in defects at the heterointerfaces and in the surface layer was induced by the effect of a direct current (DC) in a vacuum ultraviolet (UV) environment, which could provide more channels for the removal of atoms. The directed migration of atomic clusters in the films was caused by the effect of the DC, which also aggravated the defects' expansion and led to the formation of Au-Cu intermetallic compounds (IMCs). In addition, the voids formed at the interface between the Au/Cu films and the Si substrates were found to be mainly related to the generation of the material Au2Cu3.
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Affiliation(s)
- Kai Yan
- Institute of Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, China. and Department of Chemistry, Tsinghua University, Beijing 100084, China.
| | - Wenqing Yao
- Department of Chemistry, Tsinghua University, Beijing 100084, China.
| | - Liping Yang
- Department of Chemistry, Tsinghua University, Beijing 100084, China.
| | - Jiangli Cao
- Institute of Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, China.
| | - Yuanyuan Zhao
- Institute of Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, China.
| | - Lixia Zhao
- Institute of Semiconductors, Chinese Academy of Science, Beijing 100083, China
| | - Yongfa Zhu
- Department of Chemistry, Tsinghua University, Beijing 100084, China.
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10
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Chen HP, Huang CW, Wang CW, Wu WW, Liao CN, Chen LJ, Tu KN. Optimization of the nanotwin-induced zigzag surface of copper by electromigration. NANOSCALE 2016; 8:2584-8. [PMID: 26787289 DOI: 10.1039/c5nr05418d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
By adding nanotwins to Cu, the surface electromigration (EM) slows down. The atomic mobility of the surface step-edges is retarded by the triple points where a twin meets a free surface to form a zigzag-type surface. We observed that EM can alter the zigzag surface structure to optimize the reduction of EM, according to Le Chatelier's principle. Statistically, the optimal alternation is to change an arbitrary (111)/(hkl) zigzag pair to a pair having a very low index (hkl) plane, especially the (200) plane. Using in situ ultrahigh vacuum and high-resolution transmission electron microscopy, we examined the effects of different zigzag surfaces on the rate of EM. The calculated rate of surface EM can be decreased by a factor of ten.
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Affiliation(s)
- Hsin-Ping Chen
- University of California at Los Angeles, Department of Materials Science and Engineering, Los Angeles, CA 90095, USA.
| | - Chun-Wei Huang
- National Chiao Tung University, Department of Materials Science and Engineering, No. 1001, University Rd., Hsinchu 300, Taiwan.
| | - Chun-Wen Wang
- National Chiao Tung University, Department of Materials Science and Engineering, No. 1001, University Rd., Hsinchu 300, Taiwan.
| | - Wen-Wei Wu
- National Chiao Tung University, Department of Materials Science and Engineering, No. 1001, University Rd., Hsinchu 300, Taiwan.
| | - Chien-Neng Liao
- National Tsing-Hua University, Department of Materials Science and Engineering, Hsinchu 30013, Taiwan, Republic of China.
| | - Lih-Juann Chen
- National Tsing-Hua University, Department of Materials Science and Engineering, Hsinchu 30013, Taiwan, Republic of China.
| | - King-Ning Tu
- University of California at Los Angeles, Department of Materials Science and Engineering, Los Angeles, CA 90095, USA.
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11
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Wang B, Eichfield SM, Wang D, Robinson JA, Haque MA. In situ degradation studies of two-dimensional WSe₂-graphene heterostructures. NANOSCALE 2015; 7:14489-14495. [PMID: 26260468 DOI: 10.1039/c5nr03357h] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Heterostructures of two-dimensional materials can be vulnerable to thermal degradation due to structural and interfacial defects as well as thermal expansion mismatch, yet a systematic study does not exist in the literature. In this study, we investigate the degradation of freestanding WSe2-graphene heterostructures due to heat and charge flow by performing in situ experiments inside a transmission electron microscope. Experimental results show that purely thermal loading requires higher temperatures (>850 °C), about 150 °C higher than that under combined electrical and thermal loading. In both cases, selenium is the first element to decompose and migration of silicon atoms from the test structure to the freestanding specimen initiates rapid degradation through the formation of tungsten disilicide and silicon carbide. The role of the current flow is to enhance the migration of silicon from the sample holder and to knock-out the selenium atoms. The findings of this study provide fundamental insights into the degradation of WSe2-graphene heterostructures and inspire their application in electronics for use in harsh environments.
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Affiliation(s)
- B Wang
- Mechanical & Nuclear Engineering, 314 Leonhard Building. and the Pennsylvania State University, PA 16802, USA.
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12
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13
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Latz A, Sindermann SP, Brendel L, Dumpich G, Meyer zu Heringdorf FJ, Wolf DE. Anisotropy of electromigration-induced void and island drift. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2014; 26:055005. [PMID: 24356088 DOI: 10.1088/0953-8984/26/5/055005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
By means of our novel self-learning kinetic Monte Carlo model (Latz et al 2012 J. Phys.: Condens. Matter 24 485005) we study the electromigration-induced drift of monolayer voids and islands on unpassivated surfaces of single crystalline Ag(111) and Ag(001) films at the atomic scale. Regarding the drift velocity, we find a non-monotonic size dependence for small voids. The drift direction is aligned with the electromigration force only along high symmetry directions, while halfway between, the angle enclosed by them is maximal. The magnitude of these directional deviations strongly depends on the system parameter, which are investigated in detail. The simulation results are in accordance with void motion observed in experiments performed on Ag(111).
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Affiliation(s)
- A Latz
- Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, D-47057 Duisburg, Germany
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14
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Sun L, Diaz-Fernandez YA, Gschneidtner TA, Westerlund F, Lara-Avila S, Moth-Poulsen K. Single-molecule electronics: from chemical design to functional devices. Chem Soc Rev 2014; 43:7378-411. [DOI: 10.1039/c4cs00143e] [Citation(s) in RCA: 361] [Impact Index Per Article: 36.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The use of single molecules in electronics represents the next limit of miniaturisation of electronic devices, which would enable to continue the trend of aggressive downscaling of silicon-based electronic devices.
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Affiliation(s)
- Lanlan Sun
- Department of Chemical and Biological Engineering
- Chalmers University of Technology
- , Sweden
| | - Yuri A. Diaz-Fernandez
- Department of Chemical and Biological Engineering
- Chalmers University of Technology
- , Sweden
| | - Tina A. Gschneidtner
- Department of Chemical and Biological Engineering
- Chalmers University of Technology
- , Sweden
| | - Fredrik Westerlund
- Department of Chemical and Biological Engineering
- Chalmers University of Technology
- , Sweden
| | - Samuel Lara-Avila
- Department of Micro and Nanotechnology
- MC2
- Chalmers University of Technology
- , Sweden
| | - Kasper Moth-Poulsen
- Department of Chemical and Biological Engineering
- Chalmers University of Technology
- , Sweden
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15
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Kaspers MR, Bernhart AM, Bobisch CA, Möller R. Current induced surface diffusion on a single-crystalline silver nanowire. NANOTECHNOLOGY 2012; 23:205706. [PMID: 22543691 DOI: 10.1088/0957-4484/23/20/205706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Scanning tunnelling microscopy was used to study the morphological changes of the surface of a single-crystalline silver nanowire caused by a lateral electron current. At current densities of about 1.5 × 10(7) A cm(-2), surface atoms are extracted from step edges, resulting in the motion of surface steps, islands and holes with a thickness or depth of one monolayer. Upon current reversal the direction of the material transport can be altered. The findings are interpreted in terms of the wind force.
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Affiliation(s)
- M R Kaspers
- Faculty of Physics, Centre for Nanointegration Duisburg-Essen, University of Duisburg-Essen, 47048 Duisburg, Germany
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16
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Sindermann S, Witt C, Spoddig D, Horn-von Hoegen M, Dumpich G, Meyer zu Heringdorf FJ. Epitaxial Ag wires with a single grain boundary for electromigration. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2011; 82:123907. [PMID: 22225231 DOI: 10.1063/1.3671802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Test structures for electromigration with defined grain boundary configurations can be fabricated using focused ion beam (FIB). We present a novel approach of combining epitaxial growth of Ag islands with FIB milling. Depending on the growth parameters, bi-crystalline Ag islands can be grown on Si(111) surfaces and can be structured into wires by FIB. To avoid doping effects of the used Ga FIB, silicon on insulator (SOI) substrates are used. By cutting through the device layer of the SOI substrate with deep trenches, the Ag wire can be electrically separated from the rest of the substrate. In this way, Ag wires with one isolated grain boundary of arbitrary direction can be assembled. Using scanning electron microscopy we demonstrate the feasibility of our approach.
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Affiliation(s)
- S Sindermann
- Faculty of Physics and Center for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen, D-47057 Duisburg, Germany.
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17
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Bode N, Kusminskiy SV, Egger R, von Oppen F. Scattering theory of current-induced forces in mesoscopic systems. PHYSICAL REVIEW LETTERS 2011; 107:036804. [PMID: 21838389 DOI: 10.1103/physrevlett.107.036804] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2011] [Indexed: 05/07/2023]
Abstract
We develop a scattering theory of current-induced forces exerted by the conduction electrons of a general mesoscopic conductor on slow "mechanical" degrees of freedom. Our theory describes the current-induced forces both in and out of equilibrium in terms of the scattering matrix of the phase-coherent conductor. Under general nonequilibrium conditions, the resulting mechanical Langevin dynamics is subject to both nonconservative and velocity-dependent Lorentz-like forces, in addition to (possibly negative) friction. We illustrate our results with a two-mode model inspired by hydrogen molecules in a break junction which exhibits limit-cycle dynamics of the mechanical modes.
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Affiliation(s)
- Niels Bode
- Dahlem Center for Complex Quantum Systems and Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany
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18
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Maldonado A, Guillamón I, Suderow H, Vieira S. Scanning tunneling spectroscopy under large current flow through the sample. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2011; 82:073710. [PMID: 21806192 DOI: 10.1063/1.3615627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We describe a method to make scanning tunneling microscopy/spectroscopy imaging at very low temperatures while driving a constant electric current up to some tens of mA through the sample. It gives a new local probe, which we term current driven scanning tunneling microscopy/spectroscopy. We show spectroscopic and topographic measurements under the application of a current in superconducting Al and NbSe(2) at 100 mK. Perspective of applications of this local imaging method includes local vortex motion experiments, and Doppler shift local density of states studies.
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Affiliation(s)
- A Maldonado
- Laboratorio de Bajas Temperaturas, Departamento de Física de la Materia Condensada, Instituto de Ciencia de Materiales Nicolás Cabrera, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain
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19
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Bevan KH, Zhu W, Guo H, Zhang Z. Terminating surface electromigration at the source. PHYSICAL REVIEW LETTERS 2011; 106:156404. [PMID: 21568585 DOI: 10.1103/physrevlett.106.156404] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Indexed: 05/30/2023]
Abstract
Based on an extensive search across the periodic table utilizing first-principles density functional theory, we discover phosphorus to be an optimal surface electromigration inhibitor on the technologically important Cu(111) surface--the dominant diffusion pathway in modern nanoelectronics interconnects. Unrecognized thus far, such an inhibitor is characterized by energetically favoring (and binding strongly at) the kink sites of step edges. These properties are determined to generally reside in elements that form strong covalent bonds with substrate metal atoms. This finding sheds new light on the possibility of halting surface electromigration via kink blocking impurities.
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Affiliation(s)
- Kirk H Bevan
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
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