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Araki Y, Minato T, Arai T. Microscopic behavior of nano-water droplets on a silica glass surface. Sci Rep 2024; 14:10693. [PMID: 38724652 PMCID: PMC11082177 DOI: 10.1038/s41598-024-61212-1] [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: 01/24/2024] [Accepted: 05/02/2024] [Indexed: 05/12/2024] Open
Abstract
Recent advancements in computational science and interfacial measurements have sparked interest in microscopic water droplets and their diverse behaviors. A previous study using nonlinear spectroscopy revealed the heterogeneous wetting phenomenon of silica glass in response to humidity. Building on this premise, we employed high-resolution atomic force microscopy to investigate the wetting dynamics of silica glass surfaces at various humidity levels. Our observations revealed the spontaneous formation of nano-water droplets at a relative humidity of 50%. In contrast to the conventional model, which predicts the spreading of nanodroplets to form a uniform water film, our findings demonstrate the coexistence of nano-water droplets and the liquid film. Moreover, the mobility of the nano-water droplets suggests their potential in inducing the transport of adsorbates on solid surfaces. These results may contribute to the catalytic function of solid materials.
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Affiliation(s)
- Yuki Araki
- Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa, Ishikawa, 920-1192, Japan.
| | - Taketoshi Minato
- Institute for Molecular Science, National Institutes of Natural Sciences, Okazaki, Aichi, 444-8585, Japan
| | - Toyoko Arai
- Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa, Ishikawa, 920-1192, Japan
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Della Ciana M, Kovtun A, Summonte C, Candini A, Cavalcoli D, Gentili D, Nipoti R, Albonetti C. Native Silicon Oxide Properties Determined by Doping. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:12430-12451. [PMID: 37608587 DOI: 10.1021/acs.langmuir.3c01652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
The physico-chemical properties of native oxide layers, spontaneously forming on crystalline Si wafers in air, can be strictly correlated to the dopant type and doping level. In particular, our investigations focused on oxide layers formed upon air exposure in a clean room after Si wafer production, with dopant concentration levels from ≈1013 to ≈1019 cm-3. In order to determine these correlations, we studied the surface, the oxide bulk, and its interface with Si. The surface was investigated using the contact angle, thermal desorption, and atomic force microscopy measurements which provided information on surface energy, cleanliness, and morphology, respectively. Thickness was measured with ellipsometry and chemical composition with X-ray photoemission spectroscopy. Electrostatic charges within the oxide layer and at the Si interface were studied with Kelvin probe microscopy. Some properties such as thickness, showed an abrupt change, while others, including silanol concentration and Si intermediate-oxidation states, presented maxima at a critical doping concentration of ≈2.1 × 1015 cm-3. Additionally, two electrostatic contributions were found to originate from silanols present on the surface and the net charge distributed within the oxide layer. Lastly, surface roughness was also found to depend upon dopant concentration, showing a minimum at the same critical dopant concentration. These findings were reproduced for oxide layers regrown in a clean room after chemical etching of the native ones.
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Affiliation(s)
- Michele Della Ciana
- Consiglio Nazionale delle Ricerche - Istituto per lo Studio dei Materiali Nanostrutturati (CNR-ISMN), via P. Gobetti 101, 40129 Bologna, Italy
| | - Alessandro Kovtun
- Consiglio Nazionale delle Ricerche - Istituto per la Sintesi Organica e la Fotoreattività (CNR-ISOF), via P. Gobetti 101, 40129 Bologna, Italy
| | - Caterina Summonte
- Consiglio Nazionale delle Ricerche - Istituto per la Microelettronica e Microsistemi (CNR-IMM), via P. Gobetti 101, 40129 Bologna, Italy
| | - Andrea Candini
- Consiglio Nazionale delle Ricerche - Istituto per la Sintesi Organica e la Fotoreattività (CNR-ISOF), via P. Gobetti 101, 40129 Bologna, Italy
| | - Daniela Cavalcoli
- Department of Physics and Astronomy, University of Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy
| | - Denis Gentili
- Consiglio Nazionale delle Ricerche - Istituto per lo Studio dei Materiali Nanostrutturati (CNR-ISMN), via P. Gobetti 101, 40129 Bologna, Italy
| | - Roberta Nipoti
- Consiglio Nazionale delle Ricerche - Istituto per la Microelettronica e Microsistemi (CNR-IMM), via P. Gobetti 101, 40129 Bologna, Italy
| | - Cristiano Albonetti
- Consiglio Nazionale delle Ricerche - Istituto per lo Studio dei Materiali Nanostrutturati (CNR-ISMN), via P. Gobetti 101, 40129 Bologna, Italy
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Küçükcan B, Günay B, Gordesli-Duatepe FP, Sağlam Ö. Langmuir-Blodgett deposition and physicochemical surface characterization of two-dimensional perovskite nanosheets on ITO-PET substrates. Colloids Surf A Physicochem Eng Asp 2023. [DOI: 10.1016/j.colsurfa.2023.131338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
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Lee Y, You Y, Cho C, Kim S, Lee J, Kim M, Lee H, You Y, Kim K, You S. Comprehensive Assessments in Bonding Energy of Plasma Assisted Si-SiO 2 Direct Wafer Bonding after Low Temperature Rapid Thermal Annealing. MICROMACHINES 2022; 13:1856. [PMID: 36363877 PMCID: PMC9695507 DOI: 10.3390/mi13111856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Revised: 10/24/2022] [Accepted: 10/27/2022] [Indexed: 06/16/2023]
Abstract
Direct wafer bonding is one of the most attractive techniques for next-generation semiconductor devices, and plasma has been playing an indispensable role in the wider adoption of the wafer bonding technique by lowering its process temperature. Although numerous studies on plasma-assisted direct wafer bonding have been reported, there is still a lack of deep investigations focusing on the plasma itself. Other than the plasma surface treatment, the wafer bonding process includes multiple steps such as surface cleaning and annealing that require comprehensive studies to maximize the bonding strengths. In this work, we evaluate the various process steps of Si-SiO2 wafer bonding through case-by-case experimental studies, covering factors including the plasma conditions for surface treatment and secondary factors such as the time intervals between some process steps. The results show that plasma treatment with increasing input power has a trade-off between bonding strengths and interfacial voids, requiring the optimization of the plasma conditions. It is also noticeable that the effects of plasma treatment on wafer bonding can be improved when the plasma-treated wafers are stored in ambient atmosphere before the subsequent process step, which may suggest that wafer exposure to air during the bonding process is advantageous compared to processing entirely in vacuum. The results are expected to allow plasma-assisted direct wafer bonding technology to play a bigger role in the packaging process of semiconductor device manufacturing.
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Affiliation(s)
- Youngseok Lee
- Applied Physics Lab for Plasma Engineering (APPLE), Department of Physics, Chungnam National University, Daejeon 34134, Korea
| | - Yebin You
- Applied Physics Lab for Plasma Engineering (APPLE), Department of Physics, Chungnam National University, Daejeon 34134, Korea
| | - Chulhee Cho
- Applied Physics Lab for Plasma Engineering (APPLE), Department of Physics, Chungnam National University, Daejeon 34134, Korea
| | - Sijun Kim
- Applied Physics Lab for Plasma Engineering (APPLE), Department of Physics, Chungnam National University, Daejeon 34134, Korea
| | - Jangjae Lee
- Applied Physics Lab for Plasma Engineering (APPLE), Department of Physics, Chungnam National University, Daejeon 34134, Korea
| | - Minyoung Kim
- Advanced Components Research Lab, SEMES, Hwaseong-si 18383, Korea
| | - Hanglim Lee
- Advanced Components Research Lab, SEMES, Hwaseong-si 18383, Korea
| | - Youngjun You
- TP Advanced Equipment Group, SEMES, Cheonan-si 31040, Korea
| | - Kyungman Kim
- TP Advanced Equipment Group, SEMES, Cheonan-si 31040, Korea
| | - ShinJae You
- Applied Physics Lab for Plasma Engineering (APPLE), Department of Physics, Chungnam National University, Daejeon 34134, Korea
- Institute of Quantum Systems (IQS), Department of Physics, Chungnam National University, Daejeon 34134, Korea
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Rahpeima S, Dief EM, Ciampi S, Raston CL, Darwish N. Impermeable Graphene Oxide Protects Silicon from Oxidation. ACS APPLIED MATERIALS & INTERFACES 2021; 13:38799-38807. [PMID: 34342425 DOI: 10.1021/acsami.1c06495] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The presence of a natural silicon oxide (SiOx) layer over the surface of silicon (Si) has been a roadblock for hybrid semiconductor and organic electronics technology. The presence of an insulating oxide layer is a limiting operational factor, which blocks charge transfer and therefore electrical signals for a range of applications. Etching the SiOx layer by fluoride solutions leaves a reactive Si-H surface that is only stable for few hours before it starts reoxidizing under ambient conditions. Controlled passivation of silicon is also of key importance for improving Si photovoltaic efficiency. Here, we show that a thin layer of graphene oxide (GOx) prevents Si surfaces from oxidation under ambient conditions for more than 30 days. In addition, we show that the protective GOx layer can be modified with molecules enabling a functional surface that allows for further chemical conjugation or connections with upper electrodes, while preserving the underneath Si in a nonoxidized form. The GOx layer can be switched electrochemically to reduced graphene oxide, allowing the development of a dynamic material for molecular electronics technologies. These findings demonstrate that 2D materials are alternatives to organic self-assembled monolayers that are typically used to protect and tune the properties of Si and open a realm of possibilities that combine Si and 2D materials technologies.
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Affiliation(s)
- Soraya Rahpeima
- School of Molecular and Life Sciences, Curtin Institute of Functional Molecules and Interfaces, Curtin University, Bentley, Perth, Western Australia 6102, Australia
- Flinders Institute for Nanoscale Science and Technology, College of Science and Engineering, Flinders University, Bedford Park, South Australia 5042, Australia
| | - Essam M Dief
- School of Molecular and Life Sciences, Curtin Institute of Functional Molecules and Interfaces, Curtin University, Bentley, Perth, Western Australia 6102, Australia
| | - Simone Ciampi
- School of Molecular and Life Sciences, Curtin Institute of Functional Molecules and Interfaces, Curtin University, Bentley, Perth, Western Australia 6102, Australia
| | - Colin L Raston
- Flinders Institute for Nanoscale Science and Technology, College of Science and Engineering, Flinders University, Bedford Park, South Australia 5042, Australia
| | - Nadim Darwish
- School of Molecular and Life Sciences, Curtin Institute of Functional Molecules and Interfaces, Curtin University, Bentley, Perth, Western Australia 6102, Australia
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Wang M, Duan F. Atomic-Level Material Removal Mechanisms of Si(110) Chemical Mechanical Polishing: Insights from ReaxFF Reactive Molecular Dynamics Simulations. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:2161-2169. [PMID: 33530684 DOI: 10.1021/acs.langmuir.0c03416] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Reactive molecular dynamics (ReaxFF) simulations are performed to explore the atomistic mechanism of chemical mechanical polishing (CMP) processes on a Si(110) surface polished with an a-SiO2 particle. The Si surface is oxidized by reacting with water before the CMP process, and the O atoms of the oxidized Si surface mainly exist in the form of Si-O- dangling bonds and Si-O-Si bonds. In the CMP process, the insertion of O atoms into the surface, the formation of interfacial Si-O-Si and Si-Si bridge bonds, and the adsorption of H atoms on the surface-saturated Si atoms can all cause the surface bond breakage and even the Si atomic removal. The contributions of the four different kinds of tribochemical wear mechanisms to the surface wear decrease in turn and are much larger than that of mechanical wear. The results indicate that the material removal in the actual Si CMP process is the combined results of multiple atomic-level wear mechanisms. Furthermore, we find that the oxide layer of the Si surface plays an important role in the surface wear mainly by providing O atoms to insert into the surface, rather than by providing additional reaction pathways to form interfacial Si-O-Si bridge bonds. This work provides new and further insights into the process and mechanism of silicon removal during CMP.
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Affiliation(s)
- Ming Wang
- State Key Laboratory of Mechanical Transmissions, Chongqing University, Chongqing 400044, China
| | - Fangli Duan
- State Key Laboratory of Mechanical Transmissions, Chongqing University, Chongqing 400044, China
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Xiao C, Chen C, Yao Y, Liu H, Chen L, Qian L, Kim SH. Nanoasperity Adhesion of the Silicon Surface in Humid Air: The Roles of Surface Chemistry and Oxidized Layer Structures. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:5483-5491. [PMID: 32357012 DOI: 10.1021/acs.langmuir.0c00205] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The interfacial adhesion between silicon oxide surfaces is normally believed to be governed by the surface chemistry of the topmost surface affecting the water contact angle and hydrogen bonding interactions. In the case of a silicon wafer, the physical structure of the native oxide at the surface can vary drastically depending on the aging process; thus, not only the surface chemistry but also the history of surface treatment can also have a profound impact on nanoasperity adhesion. This study reports the effect of aging conditions (ambient air, liquid water, and liquid ethanol) on the nanoasperity adhesion behaviors of a silicon surface. When the silicon surface is kept in liquid alcohol, the surface remains hydrophobic, and adhesion in ambient air can be explained with the capillary effect of the liquid meniscus condensed around the annulus of the nanoasperity contact. When the silicon surface is oxidized in ambient air, the surface gradually becomes hydrophilic, and the strongly hydrogen-bonded water network of adsorbed water plays a dominant role in the nanoasperity interfacial adhesion force. When the silicon surface is aged in liquid water, the interfacial adhesion force measured in ambient air is significantly larger than the value predicted from the theoretical model based on the water contact angle and the hydrogen bonding interaction at the topmost surface. This is because the surface layer oxidized in liquid water is gel-like and thus can swell upon uptake of water from the humid air. To fully encompass all these behaviors, a solid-adsorbate-solid model predicting the adhesion force is developed by introducing a fitting parameter β, which can be adjusted depending on the adsorbed water structure and the swelling capacity of the oxidized surface layer.
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Affiliation(s)
- Chen Xiao
- Tribology Research Institute, State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu 610031, China
- Department of Chemical Engineering and Materials Research Institute, The Pennsylvania State University, University Park, State College, Pennsylvania 16802, United States
| | - Chao Chen
- Tribology Research Institute, State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu 610031, China
| | - Yangyang Yao
- Tribology Research Institute, State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu 610031, China
| | - Hongshen Liu
- Department of Chemical Engineering and Materials Research Institute, The Pennsylvania State University, University Park, State College, Pennsylvania 16802, United States
| | - Lei Chen
- Tribology Research Institute, State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu 610031, China
| | - Linmao Qian
- Tribology Research Institute, State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu 610031, China
| | - Seong H Kim
- Department of Chemical Engineering and Materials Research Institute, The Pennsylvania State University, University Park, State College, Pennsylvania 16802, United States
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