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Song TE, Oh SA, Ahn CW, Oh IK, Jeon HJ. Effective Approach for Fabricating Highly Precise High-Curvature Structural Patterns via Air-Bubble Induction. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:15785-15791. [PMID: 37880817 DOI: 10.1021/acs.langmuir.3c02454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2023]
Abstract
Developing a new master mold-based patterning technology that can be used to accurately, precisely, and uniformly create large-area micropatterns while controlling the micropatterns of curved structures is essential for promoting innovative developments in various application fields. This study develops a new top-down lithographic process that can effectively produce structural patterns with high curvatures by growing isolated microbubbles in the master pattern holes. The isolated air-pocket lithography (IAL) we developed is based on the controlled behavior of micrometer-sized air pockets trapped between the grooves of the master pattern and the curable polymer. We successfully fabricated a concave array polydimethylsiloxane (PDMS) film and a convex array polymer film. In addition, the IAL mechanism was proven by confirming the expansion process of micrometer-sized air pockets trapped between the deep groove of the silicon master pattern and the PDMS coating film by using optical microscopy images. We successfully obtained complex three-dimensional structural patterns containing both 3D hollow spherical concave and ring-shaped two-dimensional convex patterns. This simple, fast, and effective high-curvature patterning technique is expected to provide innovative solutions for future applications such as nanoelectronics, optical devices, displays, and photovoltaics.
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Affiliation(s)
- Tae-Eun Song
- National Creative Research Initiative Center for Functionally Antagonistic Nano-Engineering, Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291, Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Sang-Ah Oh
- Department of Chemical Engineering and Biotechnology, Tech University of Korea, 237, Sangidaehak-ro, Si-heung-si, Gyeonggi-do 15073, Republic of Korea
| | - Chi Won Ahn
- National Nano Fab Center (NNFC), 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Il-Kwon Oh
- National Creative Research Initiative Center for Functionally Antagonistic Nano-Engineering, Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291, Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Hwan-Jin Jeon
- Department of Chemical Engineering and Biotechnology, Tech University of Korea, 237, Sangidaehak-ro, Si-heung-si, Gyeonggi-do 15073, Republic of Korea
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Jonker D, Berenschot EJW, Tas NR, Tiggelaar RM, van Houselt A, Gardeniers HJGE. Large Dense Periodic Arrays of Vertically Aligned Sharp Silicon Nanocones. NANOSCALE RESEARCH LETTERS 2022; 17:100. [PMID: 36245035 PMCID: PMC9573847 DOI: 10.1186/s11671-022-03735-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 09/25/2022] [Indexed: 06/16/2023]
Abstract
Convex cylindrical silicon nanostructures, also referred to as silicon nanocones, find their value in many applications ranging from photovoltaics to nanofluidics, nanophotonics, and nanoelectronic applications. To fabricate silicon nanocones, both bottom-up and top-down methods can be used. The top-down method presented in this work relies on pre-shaping of silicon nanowires by ion beam etching followed by self-limited thermal oxidation. The combination of pre-shaping and oxidation obtains high-density, high aspect ratio, periodic, and vertically aligned sharp single-crystalline silicon nanocones at the wafer-scale. The homogeneity of the presented nanocones is unprecedented and may give rise to applications where numerical modeling and experiments are combined without assumptions about morphology of the nanocone. The silicon nanocones are organized in a square periodic lattice, with 250 nm pitch giving arrays containing 1.6 billion structures per square centimeter. The nanocone arrays were several mm2 in size and located centimeters apart across a 100-mm-diameter single-crystalline silicon (100) substrate. For single nanocones, tip radii of curvature < 3 nm were measured. The silicon nanocones were vertically aligned, baring a height variation of < 5 nm (< 1%) for seven adjacent nanocones, whereas the height inhomogeneity is < 80 nm (< 16%) across the full wafer scale. The height inhomogeneity can be explained by inhomogeneity present in the radii of the initial columnar polymer mask. The presented method might also be applicable to silicon micro- and nanowires derived through other top-down or bottom-up methods because of the combination of ion beam etching pre-shaping and thermal oxidation sharpening. A novel method is presented where argon ion beam etching and thermal oxidation sharpening are combined to tailor a high-density single-crystalline silicon nanowire array into a vertically aligned single-crystalline silicon nanocones array with < 3 nm apex radius of curvature tips, at the wafer scale.
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Affiliation(s)
- Dirk Jonker
- Mesoscale Chemical Systems, University of Twente, MESA+ Institute, P.O. Box 217, 7500 AE, Enschede, The Netherlands.
- Physics of Interfaces and Nanomaterials, University of Twente, MESA+ Institute, P.O. Box 217, 7500 AE, Enschede, The Netherlands.
| | - Erwin J W Berenschot
- Mesoscale Chemical Systems, University of Twente, MESA+ Institute, P.O. Box 217, 7500 AE, Enschede, The Netherlands
| | - Niels R Tas
- Mesoscale Chemical Systems, University of Twente, MESA+ Institute, P.O. Box 217, 7500 AE, Enschede, The Netherlands
| | - Roald M Tiggelaar
- NanoLab Cleanroom, University of Twente, MESA+ Institute, P.O. Box 217, 7500 AE, Enschede, The Netherlands
| | - Arie van Houselt
- Physics of Interfaces and Nanomaterials, University of Twente, MESA+ Institute, P.O. Box 217, 7500 AE, Enschede, The Netherlands
| | - Han J G E Gardeniers
- Mesoscale Chemical Systems, University of Twente, MESA+ Institute, P.O. Box 217, 7500 AE, Enschede, The Netherlands
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Bae J, Park J, Ahn H, Jin J. Optical method for simultaneous thickness measurements of two layers with a significant thickness difference. OPTICS EXPRESS 2021; 29:31615-31631. [PMID: 34615252 DOI: 10.1364/oe.440507] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 09/07/2021] [Indexed: 06/13/2023]
Abstract
In this study, an optical method that allows simultaneous thickness measurements of two different layers distributed over a broad thickness range from several tens of nanometers to a few millimeters based on the integration of a spectroscopic reflectometer and a spectral-domain interferometer is proposed. Regarding the optical configuration of the integrated system, various factors, such as the operating spectral band, the measurement beam paths, and the illumination beam type, were considered to match the measurement positions and effectively separate two measurement signals acquired using both measurement techniques. Furthermore, for the thickness measurement algorithm, a model-based analysis method for high-precision substrate thickness measurements in thin-film specimens was designed to minimize the measurement error caused by thin films, and it was confirmed that the error is decreased significantly to less than 8 nm as compared to that when using a Fourier-transform analysis. The ability to undertake simultaneous thickness measurements of both layers using the proposed system was successfully verified on a specimen consisting of silicon dioxide thin film with nominal thicknesses of 100 nm and 150 nm and a 450 µm-thick silicon substrate, resulting in the exact separation between the two layers. From measurement uncertainty evaluation of a thin-film, a substrate in a thin-film specimen, and a single substrate, the uncertainties were estimated to be 0.12 nm for the thin-film, 0.094 µm for the substrate in a thin-film specimen, and 0.076 µm for the substrate. The measurement performance of thicknesses distributed on multi-scale was verified through comparative measurements using standard measurement equipment for several reference samples.
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Mutilin SV, Prinz VY, Yakovkina LV, Gutakovskii AK. Selective MOCVD synthesis of VO 2 crystals on nanosharp Si structures. CrystEngComm 2021. [DOI: 10.1039/d0ce01072c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
High-quality single VO2 nanocrystals and ordered arrays of VO2 nanorings were selectively synthesized by chemical vapor deposition (CVD) respectively on the tip apices and on the sidewall scallops.
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Affiliation(s)
| | - Victor Ya. Prinz
- Rzhanov Institute of Semiconductor Physics SB RAS
- Novosibirsk
- Russia
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