Utkur Mirsaidov

Degree: PhD
Position: Associate Professor
Affiliation: NUS – Department of Physics
Research Type: Experiment
Office: S1A-02-01
Email: phyumm@nus.edu.sg
Contact: (65) 6516 5426
Website: https://www.mirsaidov.org/
CA2DM Publications:
2025 |
Jiang, Yingying; Wong, Zicong Marvin; Yan, Hongwei; Tan, Teck Leong; Mirsaidov, Utkur Revealing Multistep Phase Separation in Metal Alloy Nanoparticles with In Situ Transmission Electron Microscopy Journal Article ACS NANO, 19 (3), pp. 3886-3894, 2025, ISSN: 1936-0851. @article{ISI:001396476700001, title = {Revealing Multistep Phase Separation in Metal Alloy Nanoparticles with \textit{In Situ} Transmission Electron Microscopy}, author = {Yingying Jiang and Zicong Marvin Wong and Hongwei Yan and Teck Leong Tan and Utkur Mirsaidov}, doi = {10.1021/acsnano.4c16095}, times_cited = {0}, issn = {1936-0851}, year = {2025}, date = {2025-01-14}, journal = {ACS NANO}, volume = {19}, number = {3}, pages = {3886-3894}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {Phase separation plays a crucial role in many natural and industrial processes, such as the formation of clouds and minerals and the distillation of crude oil. In metals and alloys, phase separation is an important approach often utilized to improve their mechanical strength for use in construction, automobile, and aerospace manufacturing. Despite its importance in many processes, the atomic details of phase separation are largely unknown. In particular, it is unclear how a different crystal phase emerges from the parent alloy. Here, using real-time in situ transmission electron microscopy, we describe the stages of the phase separation in face-centered cubic (fcc) AuRu alloy nanoparticles, resulting in a Ru phase with a hexagonal close-packed (hcp) crystal structure. Our observation reveals that the hcp Ru phase forms in two steps: the spinodal decomposition of the alloy produces metastable fcc Ru clusters, and as they grow larger, these clusters transform into hcp Ru domains. Our calculations indicate that the primary reason for the fcc-to-hcp transformation is the size-dependent competition between the interfacial and bulk energies of Ru domains. These insights into elusive, transient steps in the phase separation of alloys can aid in engineering nanomaterials with unconventional phases.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Phase separation plays a crucial role in many natural and industrial processes, such as the formation of clouds and minerals and the distillation of crude oil. In metals and alloys, phase separation is an important approach often utilized to improve their mechanical strength for use in construction, automobile, and aerospace manufacturing. Despite its importance in many processes, the atomic details of phase separation are largely unknown. In particular, it is unclear how a different crystal phase emerges from the parent alloy. Here, using real-time in situ transmission electron microscopy, we describe the stages of the phase separation in face-centered cubic (fcc) AuRu alloy nanoparticles, resulting in a Ru phase with a hexagonal close-packed (hcp) crystal structure. Our observation reveals that the hcp Ru phase forms in two steps: the spinodal decomposition of the alloy produces metastable fcc Ru clusters, and as they grow larger, these clusters transform into hcp Ru domains. Our calculations indicate that the primary reason for the fcc-to-hcp transformation is the size-dependent competition between the interfacial and bulk energies of Ru domains. These insights into elusive, transient steps in the phase separation of alloys can aid in engineering nanomaterials with unconventional phases. |
2024 |
Erofeev, Ivan; Hartanto, Antony Winata; Khan, Muhaimin Mareum; Deng, Kerong; Kumar, Krishna; Aabdin, Zainul; Tjiu, Weng Weei; Zhang, Mingsheng; Pacco, Antoine; Philipsen, Harold; Chowdhuri, Angshuman Ray; Huynh, Han Vinh; Holsteyns, Frank; Mirsaidov, Utkur Digital Etching of Molybdenum Interconnects Using Plasma Oxidation Journal Article ADVANCED MATERIALS INTERFACES, 12 (1), 2024, ISSN: 2196-7350. @article{ISI:001357050400001, title = {Digital Etching of Molybdenum Interconnects Using Plasma Oxidation}, author = {Ivan Erofeev and Antony Winata Hartanto and Muhaimin Mareum Khan and Kerong Deng and Krishna Kumar and Zainul Aabdin and Weng Weei Tjiu and Mingsheng Zhang and Antoine Pacco and Harold Philipsen and Angshuman Ray Chowdhuri and Han Vinh Huynh and Frank Holsteyns and Utkur Mirsaidov}, doi = {10.1002/admi.202400558}, times_cited = {0}, issn = {2196-7350}, year = {2024}, date = {2024-11-12}, journal = {ADVANCED MATERIALS INTERFACES}, volume = {12}, number = {1}, publisher = {WILEY}, address = {111 RIVER ST, HOBOKEN 07030-5774, NJ USA}, abstract = {Molybdenum (Mo) has a high potential of becoming the material of choice for sub-10 nm scale metal structures in future integrated circuits (ICs). Manufacturing at this scale requires exceptional precision and consistency, so many metal processing techniques must be reconsidered. In particular, present direct wet chemical etching methods produce anisotropic etching profiles with significant surface roughness, which can be detrimental to device performance. Here, it is shown that polycrystalline Mo nanowires can be etched uniformly using a cyclic two-step "digital" method: the metal surface is first oxidized with isotropic oxygen plasma to form a layer of MoO3, which is then selectively removed using either wet chemical or dry isotropic plasma etching. These two steps are repeated in cycles until the intended metal recess is achieved. High uniformity of plasma oxidation defines the etching uniformity, and small metal recess per cycle (typically 1-2 nm) provides precise control over the etching depth. This method can replace wet etching where high etching precision is needed, enabling the reliable manufacturing of nanoscale metal interconnects.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Molybdenum (Mo) has a high potential of becoming the material of choice for sub-10 nm scale metal structures in future integrated circuits (ICs). Manufacturing at this scale requires exceptional precision and consistency, so many metal processing techniques must be reconsidered. In particular, present direct wet chemical etching methods produce anisotropic etching profiles with significant surface roughness, which can be detrimental to device performance. Here, it is shown that polycrystalline Mo nanowires can be etched uniformly using a cyclic two-step "digital" method: the metal surface is first oxidized with isotropic oxygen plasma to form a layer of MoO3, which is then selectively removed using either wet chemical or dry isotropic plasma etching. These two steps are repeated in cycles until the intended metal recess is achieved. High uniformity of plasma oxidation defines the etching uniformity, and small metal recess per cycle (typically 1-2 nm) provides precise control over the etching depth. This method can replace wet etching where high etching precision is needed, enabling the reliable manufacturing of nanoscale metal interconnects. |
Deng, Kerong; Erofeev, Ivan; Chowdhuri, Angshuman Ray; Philipsen, Harold; Aabdin, Zainul; Hartanto, Antony Winata; Tjiu, Weng Weei; Zhang, Mingsheng; Fernando, Devshan; Saidov, Khakimjon; Kumar, Krishna; Pacco, Antoine; Holsteyns, Frank; Huynh, Han Vinh; Mirsaidov, Utkur Nanoscale Wet Etching of Molybdenum Interconnects with Organic Solutions Journal Article SMALL, 20 (51), 2024, ISSN: 1613-6810. @article{ISI:001337998600001, title = {Nanoscale Wet Etching of Molybdenum Interconnects with Organic Solutions}, author = {Kerong Deng and Ivan Erofeev and Angshuman Ray Chowdhuri and Harold Philipsen and Zainul Aabdin and Antony Winata Hartanto and Weng Weei Tjiu and Mingsheng Zhang and Devshan Fernando and Khakimjon Saidov and Krishna Kumar and Antoine Pacco and Frank Holsteyns and Han Vinh Huynh and Utkur Mirsaidov}, doi = {10.1002/smll.202406713}, times_cited = {0}, issn = {1613-6810}, year = {2024}, date = {2024-10-22}, journal = {SMALL}, volume = {20}, number = {51}, publisher = {WILEY-V C H VERLAG GMBH}, address = {POSTFACH 101161, 69451 WEINHEIM, GERMANY}, abstract = {Molybdenum (Mo) has emerged as a promising material for advanced semiconductor devices, especially in the design and fabrication of interconnects requiring sub-10 nm metal nanostructures. However, current wet etching methods for Mo using aqueous solutions struggle to achieve smooth etching profiles at such scales. To address this problem, we explore wet chemical etching of patterned Mo nanowires (NWs) using an organic solution: ceric ammonium nitrate (CAN) dissolved in acetonitrile (ACN). In this study, we demonstrate two distinct etching pathways by controlling the reaction temperature: i) digital cyclic scheme at room temperature, with a self-limiting Mo recess per cycle of approximate to 1.6 nm, and ii) direct etching at elevated temperature (60 degrees C), with a time-controlled Mo recess of approximate to 2 nm min-1. These methods not only offer a highly controllable nanoscale Mo etching but also ensure smooth and uniform etching profiles independent of the crystal grain orientation of the metal.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Molybdenum (Mo) has emerged as a promising material for advanced semiconductor devices, especially in the design and fabrication of interconnects requiring sub-10 nm metal nanostructures. However, current wet etching methods for Mo using aqueous solutions struggle to achieve smooth etching profiles at such scales. To address this problem, we explore wet chemical etching of patterned Mo nanowires (NWs) using an organic solution: ceric ammonium nitrate (CAN) dissolved in acetonitrile (ACN). In this study, we demonstrate two distinct etching pathways by controlling the reaction temperature: i) digital cyclic scheme at room temperature, with a self-limiting Mo recess per cycle of approximate to 1.6 nm, and ii) direct etching at elevated temperature (60 degrees C), with a time-controlled Mo recess of approximate to 2 nm min-1. These methods not only offer a highly controllable nanoscale Mo etching but also ensure smooth and uniform etching profiles independent of the crystal grain orientation of the metal. |
Erofeev, Ivan; Saidov, Khakimjon; Baraissov, Zhaslan; Yan, Hongwei; Maurice, Jean-Luc; Panciera, Federico; Mirsaidov, Utkur 3D Shape Reconstruction of Ge Nanowires during Vapor-Liquid-Solid Growth under Modulating Electric Field Journal Article ACS NANO, 18 (34), pp. 22855-22863, 2024, ISSN: 1936-0851. @article{ISI:001289867600001, title = {3D Shape Reconstruction of Ge Nanowires during Vapor-Liquid-Solid Growth under Modulating Electric Field}, author = {Ivan Erofeev and Khakimjon Saidov and Zhaslan Baraissov and Hongwei Yan and Jean-Luc Maurice and Federico Panciera and Utkur Mirsaidov}, doi = {10.1021/acsnano.4c00087}, times_cited = {0}, issn = {1936-0851}, year = {2024}, date = {2024-08-12}, journal = {ACS NANO}, volume = {18}, number = {34}, pages = {22855-22863}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {Bottom-up growth offers precise control over the structure and geometry of semiconductor nanowires (NWs), enabling a wide range of possible shapes and seamless heterostructures for applications in nanophotonics and electronics. The most common vapor-liquid-solid (VLS) growth method features a complex interaction between the liquid metal catalyst droplet and the anisotropic structure of the crystalline NW, and the growth is mainly orchestrated by the triple-phase line (TPL). Despite the intrinsic mismatch between the droplet and the NW symmetries, its discussion has been largely avoided because of its complexity, which has led to the situation when multiple observed phenomena such as NW axial asymmetry or the oscillating truncation at the TPL still lack detailed explanation. The introduction of an electric field control of the droplet has opened even more questions, which cannot be answered without properly addressing three-dimensional (3D) structure and morphology of the NW and the droplet. This work describes the details of electric-field-controlled VLS growth of germanium (Ge) NWs using environmental transmission electron microscopy (ETEM). We perform TEM tomography of the droplet-NW system during an unperturbed growth, then track its evolution while modulating the bias potential. Using 3D finite element method (FEM) modeling and crystallographic considerations, we provide a detailed and consistent mechanism for VLS growth, which naturally explains the observed asymmetries and features of a growing NW based on its crystal structure. Our findings provide a solid framework for the fabrication of complex 3D semiconductor nanostructures with ultimate control over their morphology.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Bottom-up growth offers precise control over the structure and geometry of semiconductor nanowires (NWs), enabling a wide range of possible shapes and seamless heterostructures for applications in nanophotonics and electronics. The most common vapor-liquid-solid (VLS) growth method features a complex interaction between the liquid metal catalyst droplet and the anisotropic structure of the crystalline NW, and the growth is mainly orchestrated by the triple-phase line (TPL). Despite the intrinsic mismatch between the droplet and the NW symmetries, its discussion has been largely avoided because of its complexity, which has led to the situation when multiple observed phenomena such as NW axial asymmetry or the oscillating truncation at the TPL still lack detailed explanation. The introduction of an electric field control of the droplet has opened even more questions, which cannot be answered without properly addressing three-dimensional (3D) structure and morphology of the NW and the droplet. This work describes the details of electric-field-controlled VLS growth of germanium (Ge) NWs using environmental transmission electron microscopy (ETEM). We perform TEM tomography of the droplet-NW system during an unperturbed growth, then track its evolution while modulating the bias potential. Using 3D finite element method (FEM) modeling and crystallographic considerations, we provide a detailed and consistent mechanism for VLS growth, which naturally explains the observed asymmetries and features of a growing NW based on its crystal structure. Our findings provide a solid framework for the fabrication of complex 3D semiconductor nanostructures with ultimate control over their morphology. |
Erofeev, Ivan; Hartanto, Antony Winata; Saidov, Khakimjon; Aabdin, Zainul; Pacco, Antoine; Philipsen, Harold; Tjiu, Weng Weei; Hui, Hui Kim; Holsteyns, Frank; Mirsaidov, Utkur Solving the Annealing of Mo Interconnects for Next-Gen Integrated Circuits Journal Article ADVANCED ELECTRONIC MATERIALS, 10 (9), 2024, ISSN: 2199-160X. @article{ISI:001253872900001, title = {Solving the Annealing of Mo Interconnects for Next-Gen Integrated Circuits}, author = {Ivan Erofeev and Antony Winata Hartanto and Khakimjon Saidov and Zainul Aabdin and Antoine Pacco and Harold Philipsen and Weng Weei Tjiu and Hui Kim Hui and Frank Holsteyns and Utkur Mirsaidov}, doi = {10.1002/aelm.202400035}, times_cited = {3}, issn = {2199-160X}, year = {2024}, date = {2024-06-24}, journal = {ADVANCED ELECTRONIC MATERIALS}, volume = {10}, number = {9}, publisher = {WILEY}, address = {111 RIVER ST, HOBOKEN 07030-5774, NJ USA}, abstract = {Recent surge in demand for computational power combined with strict constraints on energy consumption requires persistent increase in the density of transistors and memory cells in integrated circuits. Metal interconnects in their current form struggle to follow the size downscaling due to materials limitations at the nanoscale, causing severe performance losses. Next-generation interconnects need new materials, and molybdenum (Mo) is considered the best choice, offering low resistivity, good scalability, and barrierless integration at a low cost. However, it requires annealing at temperatures far exceeding the currently accepted limit. In this work, the challenges of high-temperature annealing of patterned Mo nanowires are looked into, and a new approach is presented to overcome them. It is demonstrated that while a conventional annealing process improves the average grain size, it can also reduce the cross-section area, thus increasing the resistivity. Using high-resolution transmission electron microscopy (TEM) with in situ heating, the evolution of structural features in real time is directly observed. Using insights from these experiments, a cyclic pulsed annealing method is developed, and it is shown that the desired grain structure is achieved in only a few seconds, without forming the surface grooves. These findings can radically facilitate Mo integration, boosting the efficiency of future integrated circuits.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Recent surge in demand for computational power combined with strict constraints on energy consumption requires persistent increase in the density of transistors and memory cells in integrated circuits. Metal interconnects in their current form struggle to follow the size downscaling due to materials limitations at the nanoscale, causing severe performance losses. Next-generation interconnects need new materials, and molybdenum (Mo) is considered the best choice, offering low resistivity, good scalability, and barrierless integration at a low cost. However, it requires annealing at temperatures far exceeding the currently accepted limit. In this work, the challenges of high-temperature annealing of patterned Mo nanowires are looked into, and a new approach is presented to overcome them. It is demonstrated that while a conventional annealing process improves the average grain size, it can also reduce the cross-section area, thus increasing the resistivity. Using high-resolution transmission electron microscopy (TEM) with in situ heating, the evolution of structural features in real time is directly observed. Using insights from these experiments, a cyclic pulsed annealing method is developed, and it is shown that the desired grain structure is achieved in only a few seconds, without forming the surface grooves. These findings can radically facilitate Mo integration, boosting the efficiency of future integrated circuits. |
2023 |
Yang, Kou; Hu, Zhitao; Li, Xiaolai; Nikolaev, Konstantin; Hong, Gan Kai; Mamchik, Natalia; Erofeev, Ivan; Mirsaidov, Utkur M; Neto, Antonio Castro H; Blackwood, Daniel J; Shchukin, Dmitry G; Trushin, Maxim; Novoselov, Kostya S; Andreeva, Daria V Graphene oxide-polyamine preprogrammable nanoreactors with sensing capability for corrosion protection of materials Journal Article PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 120 (35), 2023, ISSN: 0027-8424. @article{ISI:001112759000007, title = {Graphene oxide-polyamine preprogrammable nanoreactors with sensing capability for corrosion protection of materials}, author = {Kou Yang and Zhitao Hu and Xiaolai Li and Konstantin Nikolaev and Gan Kai Hong and Natalia Mamchik and Ivan Erofeev and Utkur M Mirsaidov and Antonio Castro H Neto and Daniel J Blackwood and Dmitry G Shchukin and Maxim Trushin and Kostya S Novoselov and Daria V Andreeva}, doi = {10.1073/pnas.2307618120}, times_cited = {3}, issn = {0027-8424}, year = {2023}, date = {2023-08-21}, journal = {PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA}, volume = {120}, number = {35}, publisher = {NATL ACAD SCIENCES}, address = {2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA}, abstract = {Corrosion is one of the major issues for sustainable manufacturing globally. The annual global cost of corrosion is US$2.5 trillion (approximately 3.4% of the world's GDP). The traditional ways of corrosion protection (such as barriers or inhibiting) are either not very effective (in the case of barrier protection) or excessively expensive (inhibiting). Here, we demonstrate a concept of nanoreactors, which are able to controllably release or adsorb protons or hydroxides directly on corrosion sites, hence, selectively regulating the corrosion reactions. A single nanoreactor comprises a nano compartment wrapped around by a pH-sensing membrane represented, respectively, by a halloysite nanotube and a graphene oxide/polyamine envelope. A nanoreactor response is determined by the change of a signaling pH on a given corrosion site. The nanoreactors are self-assembled and suitable for mass line production. The concept creates sustainable technology for developing smart anticorrosion coatings, which are nontoxic, selective, and inexpensive.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Corrosion is one of the major issues for sustainable manufacturing globally. The annual global cost of corrosion is US$2.5 trillion (approximately 3.4% of the world's GDP). The traditional ways of corrosion protection (such as barriers or inhibiting) are either not very effective (in the case of barrier protection) or excessively expensive (inhibiting). Here, we demonstrate a concept of nanoreactors, which are able to controllably release or adsorb protons or hydroxides directly on corrosion sites, hence, selectively regulating the corrosion reactions. A single nanoreactor comprises a nano compartment wrapped around by a pH-sensing membrane represented, respectively, by a halloysite nanotube and a graphene oxide/polyamine envelope. A nanoreactor response is determined by the change of a signaling pH on a given corrosion site. The nanoreactors are self-assembled and suitable for mass line production. The concept creates sustainable technology for developing smart anticorrosion coatings, which are nontoxic, selective, and inexpensive. |