Article
Chemistry, Physical
Zhitian Shi, Konstantins Jefimovs, Antonino La Magna, Marco Stampanoni, Lucia Romano
Summary: By introducing metal electric field modulators, controlled tilted etching can be achieved by modifying the near sample surface potential, thereby changing the incident angle of ions and obtaining a tilted profile.
APPLIED SURFACE SCIENCE
(2022)
Article
Chemistry, Physical
Hye Joo Lee, Hyun Woo Tak, Seong Bae Kim, Seul Ki Kim, Tae Hyun Park, Ji Yeun Kim, Dain Sung, Wonseok Lee, Seung Bae Lee, Keunsuk Kim, Byeong Ok Cho, Young Lea Kim, Ki Chan Lee, Dong Woo Kim, Geun Young Yeom
Summary: In this study, three isomers of C4H2F6 were used to investigate the plasma and etch characteristics of SiO2 masked with an ACL. The different molecular structures of the isomers led to variations in fluorocarbon-based species and atomic species in the plasma, resulting in differences in the remaining fluorocarbon polymer and etch profiles. These differences were reduced with an increase in oxygen flow rate, allowing for highly selective SiO2 etching over the ACL mask.
APPLIED SURFACE SCIENCE
(2023)
Review
Chemistry, Analytical
Michael Huff
Summary: This paper reviews advances in reaction-ion etching (RIE) for high-aspect-ratio microfabrication, highlighting the importance of anisotropic etching for precise control of device dimensions. Newer RIE methods have enabled deeper etches and higher aspect ratios, particularly in the development and production of silicon-based micro- and nano-machined devices.
Article
Chemistry, Physical
Hyun Woo Tak, Hye Joo Lee, Long Wen, Byung Jin Kang, Dain Sung, Jeong Woon Bae, Dong Woo Kim, Wonseok Lee, Seung Bae Lee, Keunsuk Kim, Byeong Ok Cho, Young Lea Kim, Han Dock Song, Geun Young Yeom
Summary: In this study, the effects of chemical branch structure on plasma characteristics and etch characteristics of high aspect ratio ACL patterned SiO2 were investigated using three isomers with the same chemical composition. The results showed that the chemical branch structure significantly influenced the plasma properties and etch characteristics, even with the same chemical composition.
APPLIED SURFACE SCIENCE
(2022)
Article
Energy & Fuels
Shixiong Wu, Jinyu Zhang, Zedong Wang, Yuanfen Chen, Guangyong Huang, Ying Liu, Hui You
Summary: This article explores the feasibility of using glass nozzles to directly write ultra-high viscosity silver paste containing micrometer-sized particles, addressing key issues in the manufacture of solar cells such as reducing the width of conductive silver wires, increasing the aspect ratio, improving the utilization rate of silver paste, and enhancing the uniformity of silver wires.
SOLAR ENERGY MATERIALS AND SOLAR CELLS
(2023)
Article
Chemistry, Physical
Taito Yoshie, Kenji Ishikawa, Thi-Thuy-Nga Nguyen, Shih-Nan Hsiao, Takayoshi Tsutsumi, Makoto Sekine, Masaru Hori
Summary: In the fabrication of semiconductor devices, the feature profiles of high-aspect-ratio Si trenches need to be controlled considering aspect-ratio-dependent etching. This control is achieved by a cyclic process involving sustained Ar plasma, alternating injection of C4F8 and SF6, and short-period substrate bias supply. The transient behaviors of gaseous and surface reactions are currently revealed through measurement of plasma parameters using a surface wave probe and optical emission spectroscopy. By fluorinating the etched surface during the cycle and controlling the bias-supply timing, an ARDE-free Si trench feature profile can be fabricated.
APPLIED SURFACE SCIENCE
(2023)
Review
Chemistry, Multidisciplinary
Yicong Chen, Jun Chen, Zhibing Li
Summary: This article reviews the recent progress on cold cathodes with graphene as the direction, including both experimental and theoretical studies. The review emphasizes the phenomena that are absent in conventional cold cathodes but present in two-dimensional van der Waals materials, such as directionality and coherence. It also covers the fabrication of emitter structures for field emission applications, their field emission properties, and the existing field emission model.
Article
Chemistry, Physical
Min Young Yoon, H. J. Yeom, Jung Hyung Kim, Jong-Ryul Jeong, Hyo-Chang Lee
Summary: In this study, a method was developed to evaluate the plasma etching result in high-aspect-ratio trenches with ion tilting. The natural sheath curvature at the wafer edge was utilized for the evaluation. It was found that ion tilt had a significant impact on etch characteristics, including etch-stop, asymmetric and vertical etching, depending on the arrangement, location, and aspect ratio of the trench. The relationship between the electric field angle and the critical angle for ions reaching the trench bottom was analyzed to understand the etching mechanism.
APPLIED SURFACE SCIENCE
(2022)
Article
Materials Science, Multidisciplinary
Jiangtao Chen, Xinyao Chang, Shaodan Wu, Hui Ren, Yirun Zhu, Bingjun Yang, Yun Zhao, Jianbiao Chen, Yan Li
Summary: High performance cold cathodes based on carbon nanotubes (CNTs) are fabricated using a screen-printing method. The CNT cathode exhibits stable electron emission and the temperature-dependent emission is also investigated. Results show that the CNT emitters achieve a maximum emission current of 16.9 mA and a super-high current density of 562 mA cm-2 under continuous driving mode, and a peak current of 70 mA with a high current density of 2333 mA cm-2 under pulse driving mode. This work provides a new approach for designing double-high CNT cold electron sources for vacuum electronic devices requiring high current and density simultaneously.
Article
Physics, Fluids & Plasmas
Patrick Vanraes, Syam Parayil Venugopalan, Matthieu Besemer, Annemie Bogaerts
Summary: Various strategies have been developed to cope with aspect ratio dependent etching (ARDE) in chip manufacturing, but they have their own limitations. In this study, we investigated the neutral transport mechanisms in ARDE by conducting experiments and simulations. Our findings suggest that the underlying mechanisms of ARDE involve shadowing and diffuse reflection of neutrals. We also explored different methods to regulate ARDE, with promising results obtained by adjusting the initial hardmask sidewall angle.
PLASMA SOURCES SCIENCE & TECHNOLOGY
(2023)
Article
Nanoscience & Nanotechnology
Barbara A. Kazanowska, Keshab R. Sapkota, Ping Lu, A. Alec Talin, Ezra Bussmann, Taisuke Ohta, Brendan P. Gunning, Kevin S. Jones, George T. Wang
Summary: This study explores the controlled fabrication of vertical, tapered, and high-aspect ratio GaN nanowires using a two-step process. The nanowires exhibit smooth semipolar faceting and show gap size dependent turn-on voltage in their field emission properties.
Article
Chemistry, Analytical
Xiaojuan Zhou, Qiang Liu, Xiaoyu Shi, Chunli Xu, Baoxin Li
Summary: In this study, gold nanorods (AuNRs) with different aspect ratios were synthesized and characterized for their chirality using circular dichroism spectroscopy. It was found that AuNRs with larger aspect ratios exhibited stronger chiral recognition ability. The research also demonstrated successful quantitative recognition of valine enantiomers using AuNRs with an aspect ratio of 4.8, providing a method to enhance the chiral recognition ability of AuNRs.
ANALYTICA CHIMICA ACTA
(2021)
Article
Nanoscience & Nanotechnology
Hee Ju Kim, Geun Young Yeom
Summary: This study investigated the effects of bias pulsing parameters and additive gases on the nanoscale Si trench etch characteristics during Cl-2/Ar plasma etching. It was found that the bias pulsing parameters during the asynchronous pulsing can affect the etch characteristics, such as etch rate, selectivity, and ARDE. The addition of CF4 and C4F8 gases improved the etch profile, with C4F8 providing a more anisotropic Si etch profile without sidewall bowing but sacrificing etch selectivity and ARDE.
ACS APPLIED NANO MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Rikiya Kikukawa, Yasushi Ohkawa, Yoshiki Yamagiwa
Summary: An experimental setup and procedure were developed to improve the electron emission stability in the long-term operation of carbon nanotube-based field emission cathodes (FECs). By using Xe plasma processing aging method, optimal plasma processing conditions were found to enhance the emission stability and extend the lifetime of FECs.
DIAMOND AND RELATED MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Alexandr Knapek, Mohammad M. Allaham, Daniel Burda, Dinara Sobola, Michal Drozd, Miroslav Horacek
Summary: In this paper, a new theory is introduced to explain the effects of polymer-coated cathodes based on an experiment. The experimental data collected from measuring the total emission current from an electrochemically etched polymer graphite rod support the proposed theory. The study presents a physical model with an equivalent circuit to describe the behavior of the polymer-coated cathodes.
MATERIALS TODAY COMMUNICATIONS
(2023)
