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Guerguis B, Cuduvally R, Morris RJH, Arcuri G, Langelier B, Bassim N. The impact of electric field strength on the accuracy of boron dopant quantification in silicon using atom probe tomography. Ultramicroscopy 2024; 266:114034. [PMID: 39205346 DOI: 10.1016/j.ultramic.2024.114034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Revised: 07/05/2024] [Accepted: 08/18/2024] [Indexed: 09/04/2024]
Abstract
This study investigates the impact of the surface electric field on the quantification accuracy of boron (B) implanted silicon (Si) using atom probe tomography (APT). The Si Charge-State Ratio (CSR(Si) = Si2+/Si+) was used as an indirect measure of the average apex electric field during analysis. For a range of electric fields, the accuracy of the total implanted dose and the depth profile shape determined by APT was evaluated against the National Institute of Standards and Technology Standard Reference Material 2137. The radial (non-)uniformity of the detected B was also examined. At a higher surface electric field (i.e., a greater CSR(Si)), the determined B dose converges on the certified dose. Additionally, the depth profile shape tends towards that derived by secondary ion mass spectrometry. This improvement coincides with a more uniform radial B distribution, evidenced by desorption maps. In contrast, for lower surface electric fields (i.e., a lower CSR(Si)), the B dose is significantly underestimated, and the depth profile is artificially stretched. The desorption maps also indicate a highly inhomogeneous B emission localized around the center of the detector, which is believed to be an artifact of B surface migration on the tip of the sample. For the purposes of routine investigations of semiconductor devices using APT, these results illustrate the potential origin of quantification artifacts and their severity at different operating conditions, thus providing pathways towards best practices for accurate and repeatable measurements.
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Affiliation(s)
- Bavley Guerguis
- Department of Materials Science and Engineering, McMaster University, Hamilton, ON L8S 4L7, Canada.
| | - Ramya Cuduvally
- Department of Materials Science and Engineering, McMaster University, Hamilton, ON L8S 4L7, Canada; Canadian Centre for Electron Microscopy, McMaster University, Hamilton, ON L8S 4M1, Canada
| | | | - Gabriel Arcuri
- Canadian Centre for Electron Microscopy, McMaster University, Hamilton, ON L8S 4M1, Canada
| | - Brian Langelier
- Department of Materials Science and Engineering, McMaster University, Hamilton, ON L8S 4L7, Canada; Canadian Centre for Electron Microscopy, McMaster University, Hamilton, ON L8S 4M1, Canada
| | - Nabil Bassim
- Department of Materials Science and Engineering, McMaster University, Hamilton, ON L8S 4L7, Canada; Canadian Centre for Electron Microscopy, McMaster University, Hamilton, ON L8S 4M1, Canada
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2
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Klupś P, Skerratt-Love K, Kruger AA, George J, Bell AMT, Bingham PA, Moody MP, Bagot PAJ. Atom Probe Tomography Investigation of Clustering in Model P2O5-Doped Borosilicate Glasses for Nuclear Waste Vitrification. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2024:ozae059. [PMID: 38973604 DOI: 10.1093/mam/ozae059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 05/27/2024] [Accepted: 06/18/2024] [Indexed: 07/09/2024]
Abstract
Atom probe tomography (APT) has been utilized to investigate the microstructure of two model borosilicate glasses designed to understand the solubility limits of phosphorous pentoxide (P2O5). This component is found in certain high-level radioactive defence wastes destined for vitrification, where phase separation can potentially lead to a number of issues relating to the processing of the glass and its long-term chemical and structural stability. The development of suitable focused ion beam (FIB)-preparation routes and APT analysis conditions were initially determined for the model glasses, before examining their detailed microstructures. In a 3.0 mol% P2O5-doped glass, both visual inspection and sensitive statistical analysis of the APT data show homogeneous microstructures, while raising the content to 4.0 mol% initiates the formation of phosphorus-enriched nanoscale precipitates. This study confirms the expected inhomogeneities and phase separation of these glasses and offers routes to characterizing these at near-atomic scale resolution using APT.
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Affiliation(s)
- Przemyslaw Klupś
- Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, UK
| | - Katrina Skerratt-Love
- Materials and Engineering Research Institute, Sheffield Hallam University, Sheffield S1 1WB, UK
| | - Albert A Kruger
- Office of River Protection 2440 Stevens Center PI, Richland, WA 99354, USA
| | - Jaime George
- Pacific Northwest National Laboratory, PO Box 999, Richland, WA 99352, USA
| | | | - Paul A Bingham
- Materials and Engineering Research Institute, Sheffield Hallam University, Sheffield S1 1WB, UK
| | - Michael P Moody
- Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, UK
| | - Paul A J Bagot
- Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, UK
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Dialameh M, Ling YT, Bogdanowicz J, Zharinov VS, Richard O, Vandervorst W, Fleischmann C. Influence of the Emitter Shape on the Field-of-View in Atom Probe Tomography. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2024:ozae016. [PMID: 38447171 DOI: 10.1093/mam/ozae016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 01/23/2024] [Accepted: 02/18/2024] [Indexed: 03/08/2024]
Abstract
Atom probe tomography (APT) is a unique analytical technique that offers three-dimensional elemental mapping with a spatial resolution down to the sub-nanometer. When APT is applied on complex heterogenous systems and/or under certain experimental conditions, that is, laser illumination, the specimen shape can deviate from an ideal hemisphere. Insufficient consideration of this aspect can introduce artifacts in the reconstructed dataset, ultimately degrading its spatial accuracy. So far, there has been limited investigation into the detailed evolution of emitter shape and its impact on the field-of-view (FOV). In this study, we numerically and experimentally investigated the FOV for asymmetric emitters and its evolution throughout the analysis depth. Our analysis revealed that, for asymmetric emitters, the ions evaporated from the topmost region of the specimen (summit) project approximately to the detector center. Furthermore, we demonstrated the implications of this finding on the FOV location for asymmetric emitters. Based on our findings, the location of the center of the FOV can deviate from the specimen central axis with an evolution depending on the evolution of the emitter shape. This study highlights the importance of accounting for the specimen shape when developing advanced data reconstruction schemes to enhance spatial resolution and accuracy.
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Affiliation(s)
| | - Yu-Ting Ling
- Imec Vision Lab, University of Antwerp, Universiteitsplein 1, 2610 Antwerp, Belgium
| | | | | | | | | | - Claudia Fleischmann
- Imec, Kapeldreef 75, 3001 Leuven, Belgium
- Quantum Solid-State Physics Group, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium
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4
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Morris RJ, Cuduvally R, Lin J, Zhao M, Vandervorst W, Thuvander M, Fleischmann C. Field dependent study on the impact of co-evaporated multihits and ion pile-up for the apparent stoichiometric quantification of GaN and AlN. Ultramicroscopy 2022; 241:113592. [DOI: 10.1016/j.ultramic.2022.113592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 07/04/2022] [Accepted: 07/21/2022] [Indexed: 10/31/2022]
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Jin S, Su H, Qian F, Li Y, Sha G. Effects of atom probe analysis parameters on composition measurement of precipitates in an Al-Mg-Si-Cu alloy. Ultramicroscopy 2022; 235:113495. [DOI: 10.1016/j.ultramic.2022.113495] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 01/07/2022] [Accepted: 02/15/2022] [Indexed: 10/19/2022]
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Ling YT, Cools S, Bogdanowicz J, Fleischmann C, Beenhouwer JD, Sijbers J, Vandervorst W. A Bottom-Up Volume Reconstruction Method for Atom Probe Tomography. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2022; 28:1-14. [PMID: 35088688 DOI: 10.1017/s1431927621012836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
This paper describes a reconstruction method for atom probe tomography based on a bottom-up approach accounting for (i) the final tip morphology (which is frequently induced by inhomogeneous evaporation probabilities across the tip surface due to laser absorption, heat diffusion effects, and inhomogeneous material properties), (ii) the limited (and changing) field of view, and (iii) the detector efficiency. The reconstruction starts from the final tip morphology and reverses the evaporation sequence through the pseudo-deposition of defined small reconstruction volumes, which are then stacked together to create the full three-dimensional (3D) tip. The subdivision in small reconstruction volumes allows the scheme to account for the changing tip shape and field of view as evaporation proceeds. Atoms within the same small reconstruction volume are reconstructed at once by placing atoms back onto their possible lattice sites through a trajectory-matching process involving simulated and experimental hit maps. As the ejected ion trajectories are simulated using detailed electrostatic modeling inside the chamber, no simplifications have been imposed on the shape of the trajectories, projection laws, or tip surface. We demonstrate the superior performance of our approach over the conventional reconstruction method (Bas) for an asymmetrical tip shape.
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Affiliation(s)
- Yu-Ting Ling
- Imec Vision Lab, University of Antwerp, Universiteitsplein 1, 2610Antwerp, Belgium
| | - Siegfried Cools
- Applied Mathematics Group, University of Antwerp, Middelheimlaan 1, 2020Antwerp, Belgium
| | | | | | - Jan De Beenhouwer
- Imec Vision Lab, University of Antwerp, Universiteitsplein 1, 2610Antwerp, Belgium
| | - Jan Sijbers
- Imec Vision Lab, University of Antwerp, Universiteitsplein 1, 2610Antwerp, Belgium
| | - Wilfried Vandervorst
- Imec vzw, Kapeldreef 75, 3001Heverlee, Belgium
- Quantum Solid-State Physics, KU Leuven, Celestijnenlaan 200D, 3001Leuven, Belgium
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Hu R, Xue J, Wu X, Zhang Y, Zhu H, Sha G. Atom Probe Tomography Characterization of Dopant Distributions in Si FinFET: Challenges and Solutions. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2020; 26:36-45. [PMID: 31753061 DOI: 10.1017/s1431927619015137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Atom probe tomography (APT) has emerged as an important tool in characterizing three-dimensional semiconductor devices. However, the complex structure and hybrid nature of a semiconductor device can pose serious challenges to the accurate measurement of dopants. In particular, local magnification and trajectory aberration observed when analyzing hybrid materials with different evaporation fields can cause severe distortions in reconstructed geometry and uncertainty in local chemistry measurement. To address these challenges, this study systematically investigates the effect of APT sampling directions on the measurement of n-type dopants P and As in an Si fin field-effect transistor (FinFET). We demonstrate that the APT samples made with their Z-axis perpendicular to the center axis of the fin are effective to minimize the negative effects that result from evaporation field differences between the Si fin and SiO2 on reconstruction and achieve improved measurement of dopant distributions. In addition, new insights have been gained regarding the distribution of ion-implanted P and As in the Si FinFET.
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Affiliation(s)
- Rong Hu
- Herbert Gleiter Institute of Nanoscience, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, Jiangsu210094, China
| | - Jing Xue
- Herbert Gleiter Institute of Nanoscience, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, Jiangsu210094, China
| | - Xingping Wu
- Herbert Gleiter Institute of Nanoscience, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, Jiangsu210094, China
| | - Yanbo Zhang
- Institute of Microelectronics of Chinese Academy of Sciences, Beijing100029, China
| | - Huilong Zhu
- Institute of Microelectronics of Chinese Academy of Sciences, Beijing100029, China
| | - Gang Sha
- Herbert Gleiter Institute of Nanoscience, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, Jiangsu210094, China
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Yeoh WK, Hung S, Chen S, Lin Y, Lee JJ. Quantification of dopant species using atom probe tomography for semiconductor application. SURF INTERFACE ANAL 2019. [DOI: 10.1002/sia.6706] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Wai Kong Yeoh
- Failure Analysis DivisionTaiwan Semiconductor Manufacturing Company, Ltd Hsinchu Taiwan
| | - Shih‐Wei Hung
- Failure Analysis DivisionTaiwan Semiconductor Manufacturing Company, Ltd Hsinchu Taiwan
| | - Shih‐Che Chen
- Department of Materials Science and EngineeringNational Taiwan University Taipei Taiwan
| | - Yi‐Hsiang Lin
- Failure Analysis DivisionTaiwan Semiconductor Manufacturing Company, Ltd Hsinchu Taiwan
| | - Jang Jung Lee
- Failure Analysis DivisionTaiwan Semiconductor Manufacturing Company, Ltd Hsinchu Taiwan
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Martin AJ, Yatzor B. Examining the Effect of Evaporation Field on Boron Measurements in SiGe: Insights into Improving the Relationship Between APT and SIMS Measurements of Boron. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2019; 25:617-624. [PMID: 30862323 DOI: 10.1017/s1431927619000291] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Understanding and resolving discrepancies between atom probe tomography (APT) and secondary ion mass spectrometry (SIMS) measurements of B dopants in Si-based materials has long been a problem for those in the semiconductor community who wish to measure B within the source/drain SiGe of a device. APT data collection of Si-based materials is typically optimized for Si, which is logical, but perhaps not ideal for field evaporation of B. Increasing the evaporation field well beyond the typically used 28Si2+:28Si+ ratio of approximately 10:1 up to a ratio of ~200:1 is demonstrated to improve B detection while retaining well-matched Si and Ge concentrations with respect to those measured by SIMS. A range of evaporation conditions are examined from a very low field with high laser energy to an extremely high field with extremely low laser energy demonstrating problems at both far ends of the spectrum and a sweet spot when the operating conditions used produce a 28Si2+:28Si+ ratio of approximately 200:1 (in terms of total counts of each ionization state), which is more than an order of magnitude higher than normally used conditions and results in nicely matched B, Si, and Ge APT measurements with those of SIMS.
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Affiliation(s)
- Andrew J Martin
- Globalfoundries, Inc.,400 Stone Break Rd Ext, Malta, NY 12020,USA
| | - Brett Yatzor
- Globalfoundries, Inc.,400 Stone Break Rd Ext, Malta, NY 12020,USA
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Wu Y, Giddings AD, Verheijen MA, Macco B, Prosa TJ, Larson DJ, Roozeboom F, Kessels WMM. Dopant Distribution in Atomic Layer Deposited ZnO:Al Films Visualized by Transmission Electron Microscopy and Atom Probe Tomography. CHEMISTRY OF MATERIALS : A PUBLICATION OF THE AMERICAN CHEMICAL SOCIETY 2018; 30:1209-1217. [PMID: 29515290 PMCID: PMC5833938 DOI: 10.1021/acs.chemmater.7b03501] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 02/02/2018] [Indexed: 06/01/2023]
Abstract
The maximum conductivity achievable in Al-doped ZnO thin films prepared by atomic layer deposition (ALD) is limited by the low doping efficiency of Al. To better understand the limiting factors for the doping efficiency, the three-dimensional distribution of Al atoms in the ZnO host material matrix has been examined on the atomic scale using a combination of high-resolution transmission electron microscopy (TEM) and atom probe tomography (APT). Although the Al distribution in ZnO films prepared by so-called "ALD supercycles" is often presented as atomically flat δ-doped layers, in reality a broadening of the Al-dopant layers is observed with a full-width-half-maximum of ∼2 nm. In addition, an enrichment of the Al at grain boundaries is observed. The low doping efficiency for local Al densities > ∼1 nm-3 can be ascribed to the Al solubility limit in ZnO and to the suppression of the ionization of Al dopants from adjacent Al donors.
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Affiliation(s)
- Yizhi Wu
- Eindhoven
University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - A. Devin Giddings
- CAMECA
Instruments Inc., 5500 Nobel Drive, Madison, Wisconsin 53711, United States
| | - Marcel A. Verheijen
- Eindhoven
University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Bart Macco
- Eindhoven
University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Ty J. Prosa
- CAMECA
Instruments Inc., 5500 Nobel Drive, Madison, Wisconsin 53711, United States
| | - David J. Larson
- CAMECA
Instruments Inc., 5500 Nobel Drive, Madison, Wisconsin 53711, United States
| | - Fred Roozeboom
- Eindhoven
University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
- Holst
Centre, P.O. Box 8550, 5605
KN Eindhoven, The Netherlands
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11
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Melkonyan D, Fleischmann C, Veloso A, Franquet A, Bogdanowicz J, Morris RJH, Vandervorst W. Wet-chemical etching of atom probe tips for artefact free analyses of nanoscaled semiconductor structures. Ultramicroscopy 2017; 186:1-8. [PMID: 29241145 DOI: 10.1016/j.ultramic.2017.12.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2017] [Revised: 12/01/2017] [Accepted: 12/06/2017] [Indexed: 11/30/2022]
Abstract
We introduce an innovative specimen preparation method employing the selectivity of a wet-chemical etching step to improve data quality and success rates in the atom probe analysis of contemporary semiconductor devices. Firstly, on the example of an SiGe fin embedded in SiO2 we demonstrate how the selective removal of SiO2 from the final APT specimen significantly improves accuracy and reliability of the reconstructed data. With the oxide removal, we eliminate the origin of shape artefacts, i.e. the formation of a non-hemispherical tip shape, that are typically observed in the reconstructed volume of complex systems. Secondly, using the same approach, we increase success rates to ∼90% for the damage-free, 3D site-specific localization of short (250 nm), vertical Si nanowires at the specimen apex. The impact of the abrupt emitter radius change that is introduced by this specimen preparation method is evaluated as being minor using field evaporation simulation and comparison of different reconstruction schemes. The Ge content within the SiGe fin as well as the 3D boron distribution in the Si NW as resolved by atom probe analysis are in good agreement with TEM/EDS and ToF-SIMS analysis, respectively.
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Affiliation(s)
- D Melkonyan
- Instituut voor Kern- en Stralingsfysica, KU Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium; Imec vzw, Kapeldreef 75, Heverlee 3001, Belgium.
| | | | - A Veloso
- Imec vzw, Kapeldreef 75, Heverlee 3001, Belgium
| | - A Franquet
- Imec vzw, Kapeldreef 75, Heverlee 3001, Belgium
| | | | | | - W Vandervorst
- Instituut voor Kern- en Stralingsfysica, KU Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium; Imec vzw, Kapeldreef 75, Heverlee 3001, Belgium
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