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Surdo S, Barillaro G. Voltage- and Metal-assisted Chemical Etching of Micro and Nano Structures in Silicon: A Comprehensive Review. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024:e2400499. [PMID: 38644330 DOI: 10.1002/smll.202400499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 03/12/2024] [Indexed: 04/23/2024]
Abstract
Sculpting silicon at the micro and nano scales has been game-changing to mold bulk silicon properties and expand, in turn, applications of silicon beyond electronics, namely, in photonics, sensing, medicine, and mechanics, to cite a few. Voltage- and metal-assisted chemical etching (ECE and MaCE, respectively) of silicon in acidic electrolytes have emerged over other micro and nanostructuring technologies thanks to their unique etching features. ECE and MaCE have enabled the fabrication of novel structures and devices not achievable otherwise, complementing those feasible with the deep reactive ion etching (DRIE) technology, the gold standard in silicon machining. Here, a comprehensive review of ECE and MaCE for silicon micro and nano machining is provided. The chemistry and physics ruling the dissolution of silicon are dissected and similarities and differences between ECE and MaCE are discussed showing that they are the two sides of the same coin. The processes governing the anisotropic etching of designed silicon micro and nanostructures are analyzed, and the modulation of etching profile over depth is discussed. The preparation of micro- and nanostructures with tailored optical, mechanical, and thermo(electrical) properties is then addressed, and their applications in photonics, (bio)sensing, (nano)medicine, and micromechanical systems are surveyed. Eventually, ECE and MaCE are benchmarked against DRIE, and future perspectives are highlighted.
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Affiliation(s)
- Salvatore Surdo
- Dipartimento di Ingegneria dell'Informazione, Università di Pisa, via G. Caruso 16, Pisa, 56122, Italy
| | - Giuseppe Barillaro
- Dipartimento di Ingegneria dell'Informazione, Università di Pisa, via G. Caruso 16, Pisa, 56122, Italy
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2
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Truong TA, Nguyen TK, Zhao H, Nguyen NK, Dinh T, Park Y, Nguyen T, Yamauchi Y, Nguyen NT, Phan HP. Engineering Stress in Thin Films: An Innovative Pathway Toward 3D Micro and Nanosystems. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2105748. [PMID: 34874620 DOI: 10.1002/smll.202105748] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 10/23/2021] [Indexed: 06/13/2023]
Abstract
Transformation of conventional 2D platforms into unusual 3D configurations provides exciting opportunities for sensors, electronics, optical devices, and biological systems. Engineering material properties or controlling and modulating stresses in thin films to pop-up 3D structures out of standard planar surfaces has been a highly active research topic over the last decade. Implementation of 3D micro and nanoarchitectures enables unprecedented functionalities including multiplexed, monolithic mechanical sensors, vertical integration of electronics components, and recording of neuron activities in 3D organoids. This paper provides an overview on stress engineering approaches to developing 3D functional microsystems. The paper systematically presents the origin of stresses generated in thin films and methods to transform a 2D design into an out-of-plane configuration. Different types of 3D micro and nanostructures, along with their applications in several areas are discussed. The paper concludes with current technical challenges and potential approaches and applications of this fast-growing research direction.
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Affiliation(s)
- Thanh-An Truong
- Queensland Micro and Nanotechnology Centre, Griffith University, Nathan, Queensland, 4111, Australia
| | - Tuan-Khoa Nguyen
- Queensland Micro and Nanotechnology Centre, Griffith University, Nathan, Queensland, 4111, Australia
| | - Hangbo Zhao
- Department of Aerospace and Mechanical Engineering, University of Southern California, Los Angeles, CA, 90089, USA
| | - Nhat-Khuong Nguyen
- Queensland Micro and Nanotechnology Centre, Griffith University, Nathan, Queensland, 4111, Australia
| | - Toan Dinh
- Centre for Future Materials, University of Southern Queensland, Ipswich, Queensland, 4305, Australia
| | - Yoonseok Park
- Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, IL, 60208, USA
| | - Thanh Nguyen
- Centre for Future Materials, University of Southern Queensland, Ipswich, Queensland, 4305, Australia
| | - Yusuke Yamauchi
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Nam-Trung Nguyen
- Queensland Micro and Nanotechnology Centre, Griffith University, Nathan, Queensland, 4111, Australia
| | - Hoang-Phuong Phan
- Queensland Micro and Nanotechnology Centre, Griffith University, Nathan, Queensland, 4111, Australia
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3
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Plasmon‐Enhanced, Self‐Traced Nanomotors on the Surface of Silicon. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202108487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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4
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Yang J, Zheng J, Ai R, Lai Y, Chow TH, Shao L, Wang J. Plasmon-Enhanced, Self-Traced Nanomotors on the Surface of Silicon. Angew Chem Int Ed Engl 2021; 60:24958-24967. [PMID: 34535946 DOI: 10.1002/anie.202108487] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 08/29/2021] [Indexed: 11/09/2022]
Abstract
Light-driven nanomotors have attracted much attention due to their potential applications. The movement of conventional nanomotors typically occurs in the solution phase, which limits their application fields. Utilizing visible light to drive nanomotors at the solid-liquid interface represents a grand challenge due to the large friction force between the nanomotor and the solid surface. Based on the attractive plasmon resonance of Au nanocrystals, for the first time, plasmon-enhanced Au nanocrystal-based nanomotors moving at the silicon-aqueous solution interface have been developed. Such nanomotors move with a clear trace engraved on the Si surface, representing an excellent and exceptional self-traced nanomotor system. In addition, the nanomotor trace on the Si surface also provides a unique and promising approach to the fabrication of nanoscale Si patterns, which is central to many applications, including microelectronics, sensing, information storage, and optoelectronics.
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Affiliation(s)
- Jianhua Yang
- Department of Physics, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Jiapeng Zheng
- Department of Physics, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Ruoqi Ai
- Department of Physics, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Yunhe Lai
- Department of Physics, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Tsz Him Chow
- Department of Physics, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Lei Shao
- Beijing Computational Science Research Center, Beijing, 100193, China.,Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, 518057, China
| | - Jianfang Wang
- Department of Physics, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China.,Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, 518057, China
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5
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El-Bashar R, Hussein M, Hegazy SF, Badr Y, Farhat O Hameed M, Obayya SSA. Analysis of highly efficient quad-crescent-shaped Si nanowires solar cell. OPTICS EXPRESS 2021; 29:13641-13656. [PMID: 33985095 DOI: 10.1364/oe.417652] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 02/18/2021] [Indexed: 06/12/2023]
Abstract
Nanostructured semiconductor nanowires (NWs) present a smart solution for broadband absorption solar cells (SCs) with high efficiency and low-cost. In this paper, a novel design of quad crescent-shaped silicon NW SC is introduced and numerically studied. The suggested NW has quad crescent shapes which create a cavity between any adjacent NWs. Such a cavity will permit multiple light scattering with improved absorption. Additionally, new modes will be excited along the NWs, which are highly coupled with the incident light. Further, the surface reflection from the crescent NWs is decreased due to the reduced surface filling ratio. The finite difference time domain method is utilized to analyze the optical characteristics of the reported structure. The proposed NW offers short circuit current density (Jsc) of 27.8 mA/cm2 and ultimate efficiency (ηul) of 34% with an enhancement of 14% and volume reduction of 40% compared to the conventional NWs. The Jsc and ηul are improved to 35.8 mA/cm2 and 43.7% by adding a Si substrate and back reflector to the suggested crescent NWs.
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MATSUMOTO A, IWAMOTO K, SHIMADA Y, FURUKAWA K, MAJIMA S, YAE S. Formation and Dissolution of Mesoporous Layer during Metal-Particle-Assisted Etching of n-Type Silicon. ELECTROCHEMISTRY 2021. [DOI: 10.5796/electrochemistry.20-65159] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Ayumu MATSUMOTO
- Department of Chemical Engineering and Materials Science, Graduate School of Engineering, University of Hyogo
| | - Keishi IWAMOTO
- Department of Chemical Engineering and Materials Science, Graduate School of Engineering, University of Hyogo
| | - Yuki SHIMADA
- Department of Chemical Engineering and Materials Science, Graduate School of Engineering, University of Hyogo
| | - Kyohei FURUKAWA
- Department of Chemical Engineering and Materials Science, Graduate School of Engineering, University of Hyogo
| | - Shun MAJIMA
- Department of Chemical Engineering and Materials Science, Graduate School of Engineering, University of Hyogo
| | - Shinji YAE
- Department of Chemical Engineering and Materials Science, Graduate School of Engineering, University of Hyogo
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7
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Leonardi AA, Faro MJL, Irrera A. Silicon Nanowires Synthesis by Metal-Assisted Chemical Etching: A Review. NANOMATERIALS (BASEL, SWITZERLAND) 2021; 11:383. [PMID: 33546133 PMCID: PMC7913243 DOI: 10.3390/nano11020383] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 01/28/2021] [Accepted: 02/01/2021] [Indexed: 02/07/2023]
Abstract
Silicon is the undisputed leader for microelectronics among all the industrial materials and Si nanostructures flourish as natural candidates for tomorrow's technologies due to the rising of novel physical properties at the nanoscale. In particular, silicon nanowires (Si NWs) are emerging as a promising resource in different fields such as electronics, photovoltaic, photonics, and sensing. Despite the plethora of techniques available for the synthesis of Si NWs, metal-assisted chemical etching (MACE) is today a cutting-edge technology for cost-effective Si nanomaterial fabrication already adopted in several research labs. During these years, MACE demonstrates interesting results for Si NW fabrication outstanding other methods. A critical study of all the main MACE routes for Si NWs is here presented, providing the comparison among all the advantages and drawbacks for different MACE approaches. All these fabrication techniques are investigated in terms of equipment, cost, complexity of the process, repeatability, also analyzing the possibility of a commercial transfer of these technologies for microelectronics, and which one may be preferred as industrial approach.
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Affiliation(s)
- Antonio Alessio Leonardi
- Dipartimento di Fisica e Astronomia “Ettore Majorana”, Università di Catania, Via Santa Sofia 64, 95123 Catania, Italy; (A.A.L.); (M.J.L.F.)
- Consiglio Nazionale delle Ricerche—Instituto Processi Chimico-Fisici (CNR-IPCF), Viale F. Stagno D’Alcontres 37, 98158 Messina, Italy
- Consiglio Nazionale delle Ricerche—Istituto per la Microelettronica e Microsistemi (CNR-IMM) UoS Catania, Via Santa Sofia 64, 95123 Catania, Italy
| | - Maria José Lo Faro
- Dipartimento di Fisica e Astronomia “Ettore Majorana”, Università di Catania, Via Santa Sofia 64, 95123 Catania, Italy; (A.A.L.); (M.J.L.F.)
- Consiglio Nazionale delle Ricerche—Istituto per la Microelettronica e Microsistemi (CNR-IMM) UoS Catania, Via Santa Sofia 64, 95123 Catania, Italy
| | - Alessia Irrera
- Consiglio Nazionale delle Ricerche—Instituto Processi Chimico-Fisici (CNR-IPCF), Viale F. Stagno D’Alcontres 37, 98158 Messina, Italy
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8
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Romano L, Stampanoni M. Microfabrication of X-ray Optics by Metal Assisted Chemical Etching: A Review. MICROMACHINES 2020; 11:E589. [PMID: 32545633 PMCID: PMC7344591 DOI: 10.3390/mi11060589] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 06/08/2020] [Accepted: 06/10/2020] [Indexed: 11/19/2022]
Abstract
High-aspect-ratio silicon micro- and nanostructures are technologically relevant in several applications, such as microelectronics, microelectromechanical systems, sensors, thermoelectric materials, battery anodes, solar cells, photonic devices, and X-ray optics. Microfabrication is usually achieved by dry-etch with reactive ions and KOH based wet-etch, metal assisted chemical etching (MacEtch) is emerging as a new etching technique that allows huge aspect ratio for feature size in the nanoscale. To date, a specialized review of MacEtch that considers both the fundamentals and X-ray optics applications is missing in the literature. This review aims to provide a comprehensive summary including: (i) fundamental mechanism; (ii) basics and roles to perform uniform etching in direction perpendicular to the <100> Si substrate; (iii) several examples of X-ray optics fabricated by MacEtch such as line gratings, circular gratings array, Fresnel zone plates, and other X-ray lenses; (iv) materials and methods for a full fabrication of absorbing gratings and the application in X-ray grating based interferometry; and (v) future perspectives of X-ray optics fabrication. The review provides researchers and engineers with an extensive and updated understanding of the principles and applications of MacEtch as a new technology for X-ray optics fabrication.
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Affiliation(s)
- Lucia Romano
- Institute for Biomedical Engineering, ETH Zürich, 8092 Zürich, Switzerland;
- Paul Scherrer Institut, Forschungsstrasse 111, CH-5232 Villigen, Switzerland
- CNR-IMM, Department of Physics, University of Catania, 64 via S. Sofia, 95123 Catania, Italy
| | - Marco Stampanoni
- Institute for Biomedical Engineering, ETH Zürich, 8092 Zürich, Switzerland;
- Paul Scherrer Institut, Forschungsstrasse 111, CH-5232 Villigen, Switzerland
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9
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Matsumoto A, Son H, Eguchi M, Iwamoto K, Shimada Y, Furukawa K, Yae S. General corrosion during metal-assisted etching of n-type silicon using different metal catalysts of silver, gold, and platinum. RSC Adv 2019; 10:253-259. [PMID: 35492542 PMCID: PMC9048163 DOI: 10.1039/c9ra08728a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 11/29/2019] [Indexed: 12/04/2022] Open
Abstract
Metal-assisted etching is a promising technique for microfabrication of semiconductors. In this method, porous silicon (Si) can be produced with a very simple procedure, and various nanostructures can be designed by changing the catalyst patterns. The kind of metal catalysts is one of the key factors to control the porous structure. In this work, we performed the etching of n-type Si (100) in a hydrofluoric acid solution containing hydrogen peroxide in the dark using silver, gold, and platinum particles electrolessly deposited at a constant coverage, and demonstrated the difference in the porous structures obtained for the different kind of metal catalysts. By comparing the mass loss of substrates with the depth of pores formed under the metal particles, we found that general corrosion occurred on the top-surface of the Si substrate around the metal particles even under the dark condition. The general corrosion depended on the metal species and it was explained by the formation and dissolution of a mesoporous layer. The kind of metal catalysts influences the dissolution of the Si surface not only under the metal catalysts but also between them. The first report on general corrosion during metal-assisted etching of silicon.![]()
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Affiliation(s)
- Ayumu Matsumoto
- Department of Chemical Engineering and Materials Science, Graduate School of Engineering, University of Hyogo 2167 Shosha Himeji Hyogo 671-2280 Japan
| | - Hikoyoshi Son
- Department of Chemical Engineering and Materials Science, Graduate School of Engineering, University of Hyogo 2167 Shosha Himeji Hyogo 671-2280 Japan
| | - Makiho Eguchi
- Department of Chemical Engineering and Materials Science, Graduate School of Engineering, University of Hyogo 2167 Shosha Himeji Hyogo 671-2280 Japan
| | - Keishi Iwamoto
- Department of Chemical Engineering and Materials Science, Graduate School of Engineering, University of Hyogo 2167 Shosha Himeji Hyogo 671-2280 Japan
| | - Yuki Shimada
- Department of Chemical Engineering and Materials Science, Graduate School of Engineering, University of Hyogo 2167 Shosha Himeji Hyogo 671-2280 Japan
| | - Kyohei Furukawa
- Department of Chemical Engineering and Materials Science, Graduate School of Engineering, University of Hyogo 2167 Shosha Himeji Hyogo 671-2280 Japan
| | - Shinji Yae
- Department of Chemical Engineering and Materials Science, Graduate School of Engineering, University of Hyogo 2167 Shosha Himeji Hyogo 671-2280 Japan
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10
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Gorkunov MV, Rogov OY, Kondratov AV, Artemov VV, Gainutdinov RV, Ezhov AA. Chiral visible light metasurface patterned in monocrystalline silicon by focused ion beam. Sci Rep 2018; 8:11623. [PMID: 30072737 PMCID: PMC6072796 DOI: 10.1038/s41598-018-29977-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 07/18/2018] [Indexed: 11/29/2022] Open
Abstract
High refractive index makes silicon the optimal platform for dielectric metasurfaces capable of versatile control of light. Among various silicon modifications, its monocrystalline form has the weakest visible light absorption but requires a careful choice of the fabrication technique to avoid damage, contamination or amorphization. Presently prevailing chemical etching can shape thin silicon layers into two-dimensional patterns consisting of strips and posts with vertical walls and equal height. Here, the possibility to create silicon nanostructure of truly tree-dimensional shape by means of the focused ion beam lithography is explored, and a 300 nm thin film of monocrystalline epitaxial silicon on sapphire is patterned with a chiral nanoscale relief. It is demonstrated that exposing silicon to the ion beam causes a substantial drop of the visible transparency, which, however, is completely restored by annealing with oxidation of the damaged surface layer. As a result, the fabricated chiral metasurface combines high (50–80%) transmittance with the circular dichroism of up to 0.5 and the optical activity of up to 20° in the visible range. Being also remarkably durable, it possesses crystal-grade hardness, heat resistance up to 1000 °C and the inertness of glass.
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Affiliation(s)
- Maxim V Gorkunov
- Shubnikov Institute of Crystallography, Federal Scientific Research Centre "Crystallography and Photonics", Russian Academy of Sciences, Moscow, 119333, Russia. .,National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Moscow, 115409, Russia.
| | - Oleg Y Rogov
- Shubnikov Institute of Crystallography, Federal Scientific Research Centre "Crystallography and Photonics", Russian Academy of Sciences, Moscow, 119333, Russia
| | - Alexey V Kondratov
- Shubnikov Institute of Crystallography, Federal Scientific Research Centre "Crystallography and Photonics", Russian Academy of Sciences, Moscow, 119333, Russia
| | - Vladimir V Artemov
- Shubnikov Institute of Crystallography, Federal Scientific Research Centre "Crystallography and Photonics", Russian Academy of Sciences, Moscow, 119333, Russia
| | - Radmir V Gainutdinov
- Shubnikov Institute of Crystallography, Federal Scientific Research Centre "Crystallography and Photonics", Russian Academy of Sciences, Moscow, 119333, Russia
| | - Alexander A Ezhov
- Shubnikov Institute of Crystallography, Federal Scientific Research Centre "Crystallography and Photonics", Russian Academy of Sciences, Moscow, 119333, Russia.,Faculty of Physics, Lomonosov Moscow State University, Moscow, 119991, Russia.,Topchiev Institute of Petrochemical Synthesis, Russian Academy of Science, Moscow, 119991, Russia
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11
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Zhang J, Zhang L, Han L, Tian ZW, Tian ZQ, Zhan D. Electrochemical nanoimprint lithography: when nanoimprint lithography meets metal assisted chemical etching. NANOSCALE 2017; 9:7476-7482. [PMID: 28530294 DOI: 10.1039/c7nr01777d] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The functional three dimensional micro-nanostructures (3D-MNS) play crucial roles in integrated and miniaturized systems because of the excellent physical, mechanical, electric and optical properties. Nanoimprint lithography (NIL) has been versatile in the fabrication of 3D-MNS by pressing thermoplastic and photocuring resists into the imprint mold. However, direct nanoimprint on the semiconductor wafer still remains a great challenge. On the other hand, considered as a competitive fabrication method for erect high-aspect 3D-MNS, metal assisted chemical etching (MacEtch) can remove the semiconductor by spontaneous corrosion reaction at the metal/semiconductor/electrolyte 3-phase interface. Moreover, it was difficult for MacEtch to fabricate multilevel or continuously curved 3D-MNS. The question of the consequences of NIL meeting the MacEtch is yet to be answered. By employing a platinum (Pt) metalized imprint mode, we demonstrated that using electrochemical nanoimprint lithography (ECNL) it was possible to fabricate not only erect 3D-MNS, but also complex 3D-MNS with multilevel stages with continuously curved surface profiles on a gallium arsenide (GaAs) wafer. A concave microlens array with an average diameter of 58.4 μm and height of 1.5 μm was obtained on a ∼1 cm2-area GaAs wafer. An 8-phase microlens array was fabricated with a minimum stage of 57 nm and machining accuracy of 2 nm, presenting an excellent optical diffraction property. Inheriting all the advantages of both NIL and MacEtch, ECNL has prospective applications in the micro/nano-fabrications of semiconductors.
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Affiliation(s)
- Jie Zhang
- State Key Laboratory of Physical Chemistry of Solid Surfaces (PCOSS), Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
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12
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Liu XL, Tsunega S, Jin RH. Self-directing chiral information in solid-solid transformation: unusual chiral-transfer without racemization from amorphous silica to crystalline silicon. NANOSCALE HORIZONS 2017; 2:147-155. [PMID: 32260658 DOI: 10.1039/c6nh00214e] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Constructing novel chiral inorganic nanomaterials is an emerging branch in chirality research. In this work, by employing a solid magnesiothermic reaction at 500-600 °C, we reduced chiral SiO2 nanofibers with average diameter ∼10 nm into chiral Si nanoplates with a size of about several hundred nm. The chirality of the as-prepared Si was judged by the pair of signals with a mirror relationship between 400-500 nm that appeared on the solid-state diffuse reflectance circular dichroism (DRCD) spectra for the l- and d-form Si. Furthermore, the chirality was also confirmed by induced vibrational circular dichroism (VCD) signals corresponding to the absorption bands in the infrared range of achiral organics (polyvinylpyrrolidone K90 and trimethoxyphenylsilane) absorbed onto chiral Si. The as-used SiO2 nanofibers possessed an ultra high-temperature (up to 900 °C) resistant chirality, which would be due to the asymmetric arrangement of Si and O atoms in small chiral domains (<10 nm) on the Si-O-Si network of SiO2. During the removal of oxygen atoms from Si-O-Si by Mg atoms, the arrangement of newly formed Si-Si bonds as well as the growth of Si crystals were still templated without racemization from the chiral information in SiO2. Consequently, the subnano/nano-scale (<10 nm) chiral information was in situ transferred via the so-called self-transfer mechanism, even though there was no retention of the outward shapes of the length-scale nanofiber SiO2 reactants in the Si products. This work offers a feasible chemical method to prepare chiral Si using abundant SiO2 raw materials.
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Affiliation(s)
- Xin-Ling Liu
- Department of Material and Life Chemistry, Kanagawa University, 3-27-1 Rokkakubashi, Kanagawa-ku, Yokohama 221-8686, Japan.
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13
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Zhang J, Zhang L, Wang W, Han L, Jia JC, Tian ZW, Tian ZQ, Zhan D. Contact electrification induced interfacial reactions and direct electrochemical nanoimprint lithography in n-type gallium arsenate wafer. Chem Sci 2017; 8:2407-2412. [PMID: 28451347 PMCID: PMC5369340 DOI: 10.1039/c6sc04091h] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 12/16/2016] [Indexed: 11/21/2022] Open
Abstract
Although metal assisted chemical etching (MacEtch) has emerged as a versatile micro-nanofabrication method for semiconductors, the chemical mechanism remains ambiguous in terms of both thermodynamics and kinetics. Here we demonstrate an innovative phenomenon, i.e., the contact electrification between platinum (Pt) and an n-type gallium arsenide (100) wafer (n-GaAs) can induce interfacial redox reactions. Because of their different work functions, when the Pt electrode comes into contact with n-GaAs, electrons will move from n-GaAs to Pt and form a contact electric field at the Pt/n-GaAs junction until their electron Fermi levels (EF) become equal. In the presence of an electrolyte, the potential of the Pt/electrolyte interface will shift due to the contact electricity and induce the spontaneous reduction of MnO4- anions on the Pt surface. Because the equilibrium of contact electrification is disturbed, electrons will transfer from n-GaAs to Pt through the tunneling effect. Thus, the accumulated positive holes at the n-GaAs/electrolyte interface make n-GaAs dissolve anodically along the Pt/n-GaAs/electrolyte 3-phase interface. Based on this principle, we developed a direct electrochemical nanoimprint lithography method applicable to crystalline semiconductors.
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Affiliation(s)
- Jie Zhang
- State Key Laboratory of Physical Chemistry of Solid Surfaces (PCOSS) , Collaborative Innovation Centre of Chemistry for Energy Materials (iChEM) , Department of Chemistry , College of Chemistry and Chemical Engineering , Xiamen University , Xiamen 361005 , China .
| | - Lin Zhang
- State Key Laboratory of Physical Chemistry of Solid Surfaces (PCOSS) , Collaborative Innovation Centre of Chemistry for Energy Materials (iChEM) , Department of Chemistry , College of Chemistry and Chemical Engineering , Xiamen University , Xiamen 361005 , China .
| | - Wei Wang
- State Key Laboratory of Physical Chemistry of Solid Surfaces (PCOSS) , Collaborative Innovation Centre of Chemistry for Energy Materials (iChEM) , Department of Chemistry , College of Chemistry and Chemical Engineering , Xiamen University , Xiamen 361005 , China .
| | - Lianhuan Han
- State Key Laboratory of Physical Chemistry of Solid Surfaces (PCOSS) , Collaborative Innovation Centre of Chemistry for Energy Materials (iChEM) , Department of Chemistry , College of Chemistry and Chemical Engineering , Xiamen University , Xiamen 361005 , China .
| | - Jing-Chun Jia
- State Key Laboratory of Physical Chemistry of Solid Surfaces (PCOSS) , Collaborative Innovation Centre of Chemistry for Energy Materials (iChEM) , Department of Chemistry , College of Chemistry and Chemical Engineering , Xiamen University , Xiamen 361005 , China .
| | - Zhao-Wu Tian
- State Key Laboratory of Physical Chemistry of Solid Surfaces (PCOSS) , Collaborative Innovation Centre of Chemistry for Energy Materials (iChEM) , Department of Chemistry , College of Chemistry and Chemical Engineering , Xiamen University , Xiamen 361005 , China .
| | - Zhong-Qun Tian
- State Key Laboratory of Physical Chemistry of Solid Surfaces (PCOSS) , Collaborative Innovation Centre of Chemistry for Energy Materials (iChEM) , Department of Chemistry , College of Chemistry and Chemical Engineering , Xiamen University , Xiamen 361005 , China .
| | - Dongping Zhan
- State Key Laboratory of Physical Chemistry of Solid Surfaces (PCOSS) , Collaborative Innovation Centre of Chemistry for Energy Materials (iChEM) , Department of Chemistry , College of Chemistry and Chemical Engineering , Xiamen University , Xiamen 361005 , China .
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14
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Zhan D, Han L, Zhang J, He Q, Tian ZW, Tian ZQ. Electrochemical micro/nano-machining: principles and practices. Chem Soc Rev 2017; 46:1526-1544. [DOI: 10.1039/c6cs00735j] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Micro/nano-machining (MNM) is becoming the cutting-edge of high-tech manufacturing because of the ever increasing industrial demands for super smooth surfaces and functional three-dimensional micro/nano-structures in miniaturized and integrate devices, and electrochemistry plays an irreplaceable role in MNM.
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Affiliation(s)
- Dongping Zhan
- State Key Laboratory of Physical Chemistry of Solid Surfaces (PCOSS)
- Collaborative Innovation Centre of Chemistry for Energy Materials (iChEM), and Department of Chemistry
- College of Chemistry and Chemical Engineering
- Xiamen University
- Xiamen 361005
| | - Lianhuan Han
- State Key Laboratory of Physical Chemistry of Solid Surfaces (PCOSS)
- Collaborative Innovation Centre of Chemistry for Energy Materials (iChEM), and Department of Chemistry
- College of Chemistry and Chemical Engineering
- Xiamen University
- Xiamen 361005
| | - Jie Zhang
- State Key Laboratory of Physical Chemistry of Solid Surfaces (PCOSS)
- Collaborative Innovation Centre of Chemistry for Energy Materials (iChEM), and Department of Chemistry
- College of Chemistry and Chemical Engineering
- Xiamen University
- Xiamen 361005
| | - Quanfeng He
- State Key Laboratory of Physical Chemistry of Solid Surfaces (PCOSS)
- Collaborative Innovation Centre of Chemistry for Energy Materials (iChEM), and Department of Chemistry
- College of Chemistry and Chemical Engineering
- Xiamen University
- Xiamen 361005
| | - Zhao-Wu Tian
- State Key Laboratory of Physical Chemistry of Solid Surfaces (PCOSS)
- Collaborative Innovation Centre of Chemistry for Energy Materials (iChEM), and Department of Chemistry
- College of Chemistry and Chemical Engineering
- Xiamen University
- Xiamen 361005
| | - Zhong-Qun Tian
- State Key Laboratory of Physical Chemistry of Solid Surfaces (PCOSS)
- Collaborative Innovation Centre of Chemistry for Energy Materials (iChEM), and Department of Chemistry
- College of Chemistry and Chemical Engineering
- Xiamen University
- Xiamen 361005
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15
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Lee S, Park B, Kim JS, Kim TI. Designs and processes toward high-aspect-ratio nanostructures at the deep nanoscale: unconventional nanolithography and its applications. NANOTECHNOLOGY 2016; 27:474001. [PMID: 27775918 DOI: 10.1088/0957-4484/27/47/474001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The patterning of high-resolution-featured deep-nanoscale structures with a high aspect ratio (AR) has received increasing attention in recent years as a promising technique for a wide range of applications, including electrical, optical, mechanical and biological systems. Despite extensive efforts to develop viable nanostructure fabrication processes, a superior technique enabling defect-free, high-resolution control over a large area is still required. In this review, we focus on recent important advances in the designs and processes of high-resolution nanostructures possessing a high AR, including hierarchical and 3D patterns. The unique applications of these materials are also discussed.
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Affiliation(s)
- Sori Lee
- School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon 440-746, Korea
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16
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Lai CQ, Zheng W, Choi WK, Thompson CV. Metal assisted anodic etching of silicon. NANOSCALE 2015; 7:11123-11134. [PMID: 26059556 DOI: 10.1039/c5nr01916h] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Metal assisted anodic etching (MAAE) of Si in HF, without H2O2, is demonstrated. Si wafers were coated with Au films, and the Au films were patterned with an array of holes. A Pt mesh was used as the cathode while the anodic contact was made through either the patterned Au film or the back side of the Si wafer. Experiments were carried out on P-type, N-type, P(+)-type and N(+)-type Si wafers and a wide range of nanostructure morphologies were observed, including solid Si nanowires, porous Si nanowires, a porous Si layer without Si nanowires, and porous Si nanowires on a thick porous Si layer. Formation of wires was the result of selective etching at the Au-Si interface. It was found that when the anodic contact was made through P-type or P(+)-type Si, regular anodic etching due to electronic hole injection leads to formation of porous silicon simultaneously with metal assisted anodic etching. When the anodic contact was made through N-type or N(+)-type Si, generation of electronic holes through processes such as impact ionization and tunnelling-assisted surface generation were required for etching. In addition, it was found that metal assisted anodic etching of Si with the anodic contact made through the patterned Au film essentially reproduces the phenomenology of metal assisted chemical etching (MACE), in which holes are generated through metal assisted reduction of H2O2 rather than current flow. These results clarify the linked roles of electrical and chemical processes that occur during electrochemical etching of Si.
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Affiliation(s)
- Chang Quan Lai
- Advanced Materials for Micro- and Nano-Systems Programme, Singapore-MIT Alliance, National University of Singapore, Singapore 117583, Singapore
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17
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Li L, Liu Y, Zhao X, Lin Z, Wong CP. Uniform vertical trench etching on silicon with high aspect ratio by metal-assisted chemical etching using nanoporous catalysts. ACS APPLIED MATERIALS & INTERFACES 2014; 6:575-84. [PMID: 24261312 DOI: 10.1021/am4046519] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Recently, metal-assisted chemical etching (MaCE) has been proposed as a promising wet-etching method for the fabrication of micro- and nanostructures on silicon with low cost. However, uniform vertical trench etching with high aspect ratio is still of great challenge for traditional MaCE. Here we report an innovated MaCE method, which combined the use of a nanoporous gold thin film as the catalyst and a hydrofluoric acid (HF)-hydrogen peroxide (H2O2) mixture solution with a low HF-to-H2O2 concentration ratio (ρ) as the etchant. The reported method successfully fabricated vertical trenches on silicon with a width down to 2 μm and an aspect ratio of 16. The geometry of the trenches was highly uniform throughout the 3D space. The vertical etching direction was favored on both (100)- and (111)-oriented silicon substrates. The reported method was also capable of producing multiple trenches on the same substrate with individually-tunable lateral geometry. An etching mechanism including a through-catalyst mass-transport process and an electropolishing-favored charge-transport process was identified by a comparative study. The novel method fundamentally solves the problems of distortion and random movement of isolated catalysts in MaCE. The results mark a breakthrough in high-quality silicon trench-etching technology with a cost of more than 2 orders of magnitude lower than that of the currently available methods.
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Affiliation(s)
- Liyi Li
- School of Materials Science and Engineering, Georgia Institute of Technology , 771 Ferst Drive, Atlanta, Georgia 30332, United States
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18
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Ho JW, Wee Q, Dumond J, Tay A, Chua SJ. Versatile pattern generation of periodic, high aspect ratio Si nanostructure arrays with sub-50-nm resolution on a wafer scale. NANOSCALE RESEARCH LETTERS 2013; 8:506. [PMID: 24289275 PMCID: PMC4219178 DOI: 10.1186/1556-276x-8-506] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Accepted: 11/23/2013] [Indexed: 05/30/2023]
Abstract
We report on a method of fabricating variable patterns of periodic, high aspect ratio silicon nanostructures with sub-50-nm resolution on a wafer scale. The approach marries step-and-repeat nanoimprint lithography (NIL) and metal-catalyzed electroless etching (MCEE), enabling near perfectly ordered Si nanostructure arrays of user-defined patterns to be controllably and rapidly generated on a wafer scale. Periodic features possessing circular, hexagonal, and rectangular cross-sections with lateral dimensions down to sub-50 nm, in hexagonal or square array configurations and high array packing densities up to 5.13 × 107 structures/mm2 not achievable by conventional UV photolithography are fabricated using this top-down approach. By suitably tuning the duration of catalytic etching, variable aspect ratio Si nanostructures can be formed. As the etched Si pattern depends largely on the NIL mould which is patterned by electron beam lithography (EBL), the technique can be used to form patterns not possible with self-assembly methods, nanosphere, and interference lithography for replication on a wafer scale. Good chemical resistance of the nanoimprinted mask and adhesion to the Si substrate facilitate good pattern transfer and preserve the smooth top surface morphology of the Si nanostructures as shown in TEM. This approach is suitable for generating Si nanostructures of controlled dimensions and patterns, with high aspect ratio on a wafer level suitable for semiconductor device production.
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Affiliation(s)
- Jian-Wei Ho
- NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Centre for Life Sciences, #05-01, 28 Medical Drive, Singapore 117456, Singapore
- Centre for Optoelectronics, Department of Electrical and Computer Engineering, National University of Singapore, Block E3 02-07, Engineering Drive 3, Singapore 119260, Singapore
- Institute of Materials Research and Engineering, Agency for Science Technology and Research (A*STAR), 3 Research Link, Singapore 117602, Singapore
| | - Qixun Wee
- Centre for Optoelectronics, Department of Electrical and Computer Engineering, National University of Singapore, Block E3 02-07, Engineering Drive 3, Singapore 119260, Singapore
- Institute of Materials Research and Engineering, Agency for Science Technology and Research (A*STAR), 3 Research Link, Singapore 117602, Singapore
- Singapore-MIT Alliance, National University of Singapore, Block E4 04-10, 4 Engineering Drive 3, Singapore 117576, Singapore
| | - Jarrett Dumond
- Institute of Materials Research and Engineering, Agency for Science Technology and Research (A*STAR), 3 Research Link, Singapore 117602, Singapore
| | - Andrew Tay
- Department of Mechanical Engineering, National University of Singapore, Block EA 07-08, 9 Engineering Drive 1, Singapore 117576, Singapore
| | - Soo-Jin Chua
- Centre for Optoelectronics, Department of Electrical and Computer Engineering, National University of Singapore, Block E3 02-07, Engineering Drive 3, Singapore 119260, Singapore
- Institute of Materials Research and Engineering, Agency for Science Technology and Research (A*STAR), 3 Research Link, Singapore 117602, Singapore
- Singapore-MIT Alliance, National University of Singapore, Block E4 04-10, 4 Engineering Drive 3, Singapore 117576, Singapore
- Singapore-MIT Alliance for Research and Technology Center, 1 CREATE Way, #10-01 CREATE Tower, Singapore 138602, Singapore
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19
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Hildreth OJ, Rykaczewski K, Fedorov AG, Wong CP. A DLVO model for catalyst motion in metal-assisted chemical etching based upon controlled out-of-plane rotational etching and force-displacement measurements. NANOSCALE 2013; 5:961-970. [PMID: 23238167 DOI: 10.1039/c2nr32293e] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Metal-assisted Chemical Etching of silicon has recently emerged as a powerful technique to fabricate 1D, 2D, and 3D nanostructures in silicon with high feature fidelity. This work demonstrates that out-of-plane rotational catalysts utilizing polymer pinning structures can be designed with excellent control over rotation angle. A plastic deformation model was developed establishing that the catalyst is driven into the silicon substrate with a minimum pressure differential across the catalyst thickness of 0.4-0.6 MPa. Force-displacement curves were gathered between an Au tip and Si or SiO(2) substrates under acidic conditions to show that Derjaguin and Landau, Verwey and Overbeek (DLVO) based forces are capable of providing restorative forces on the order of 0.2-0.3 nN with a calculated 11-18 MPa pressure differential across the catalyst. This work illustrates that out-of-plane rotational structures can be designed with controllable rotation and also suggests a new model for the driving force for catalyst motion based on DLVO theory. This process enables the facile fabrication of vertically aligned thin-film metallic structures and scalloped nanostructures in silicon for applications in 3D micro/nano-electromechanical systems, photonic devices, nanofluidics, etc.
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Affiliation(s)
- Owen J Hildreth
- School of Materials Science and Engineering, Georgia Institute of Technology, 771 Ferst Drive, Atlanta, USA.
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