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, Multidisciplinary
Martyna Michalska, Alessandro Rossi, Gasper Kokot, Callum M. M. Macdonald, Silvia Cipiccia, Peter R. T. Munro, Alessandro Olivo, Ioannis Papakonstantinou
Summary: This paper presents a method for fabricating high-aspect ratio nanogratings, which have important applications in X-ray imaging. By combining laser interference and nanoimprint lithography, physical vapor deposition, metal assisted chemical etching, and electroplating, the fabrication challenges are overcome. The results show that the fabricated nanogratings have aspect ratios exceeding 40, and they exhibit excellent diffractive abilities when exposed to a hard X-ray beam, suggesting potential applicability in phase-based X-ray imaging.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Polymer Science
Vitor Vlnieska, Evgeniia Gilshtein, Danays Kunka, Jakob Heier, Yaroslav E. Romanyuk
Summary: This study explores the use of aerosol jet printing (AJP) for 3D printing of free-standing pillar arrays. Using aryl epoxy photopolymer ink coupled with a cross-linking on the fly technique, pillar structures with a diameter of 50 μm and a height of 550 μm were successfully printed. The study also finds that satellite droplets and overspray are unavoidable for structures smaller than 70 μm, but can be mitigated by reactive ion etching (RIE) as a post-processing step.
Article
Chemistry, Multidisciplinary
Philipp Taus, Adrian Prinz, Heinz D. Wanzenboeck, Patrick Schuller, Anton Tsenov, Markus Schinnerl, Mostafa M. Shawrav, Michael Haslinger, Michael Muehlberger
Summary: This study demonstrates different approaches for generating sophisticated undercut T-shaped masters suitable for nanoimprint lithography, successfully fabricating single-layer and multilayer undercut T-shaped structures, which can be applied to replicate structural colors on artificial surfaces in the future.
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)
Article
Engineering, Electrical & Electronic
Zhitian Shi, Konstantins Jefimovs, Marco Stampanoni, Lucia Romano
Summary: This paper introduces a method for realizing protruding sharp silicon nanopillar arrays by using displacement Talbot lithography combined with metal-assisted chemical etching in the gas phase. This combination allows for reliable and low-cost fabrication of large-scale ordered nanopillar arrays. Incorporating controlled uniformity of feature size, spatial frequency doubling, and high resolution of Talbot lithography, this proposed method provides an easy-to-scale-up processing for producing silicon pillar arrays for valuable applications in both micro and nano scales.
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
(2023)
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
Optics
Hojung Choi, Joohoon Kim, Wonjoong Kim, Junhwa Seong, Chanwoong Park, Minseok Choi, Nakhyun Kim, Jisung Ha, Cheng-Wei Qiu, Junsuk Rho, Heon Lee
Summary: Nanoimprint lithography (NIL) is an attractive fabrication method for dielectric metalenses due to its low cost and high throughput. However, conventional NIL using a hard-polydimethylsiloxane (h-PDMS) mold incurs shear stress on high aspect ratio (HAR) nanostructures, leading to structural failure. In this study, a novel wet etching NIL method is proposed using a water-soluble replica mold made of polyvinyl alcohol (PVA) to fabricate flawless HAR metalenses. The printed metalenses demonstrate diffraction-limited focusing, making them ideal lenses in the visible regime. This method has potential for the low-cost, high-throughput manufacturing of various nanophotonic devices requiring HAR nanostructures, thereby facilitating commercialization.
Article
Engineering, Electrical & Electronic
Mandy Grube, Benjamin Schille, Matthias Schirmer, Maik Gerngross, Uwe Huebner, Paul Voigt, Sascha Brose
Summary: Researchers developed the hydrogen silsesquioxane-based e-beam resist Medusa 82 with improved characteristics in terms of prolonged shelf-life and larger processing window, allowing for delay between layer preparation and exposure. Medusa 82 resist compositions tolerate storage at room temperature for several weeks and provide enhanced sensitivity and contrast, simplifying the manufacturing process of micro-optical devices.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B
(2021)
Article
Engineering, Electrical & Electronic
Shuai Zhao, Guodong Yuan, Qiuhao Zhu, Luhang Song, Di Zhang, Yumeng Liu, Jun Lu, Weihua Han, Junwei Luo
Summary: This study finds that reactive ion etching (RIE) introduces atomic steps and charged traps, severely degrading the cryogenic mobility of Si-based MOS devices. By using a post-RIE high-temperature SiO2 regrowth process, these damages can be successfully removed, leading to enhanced cryogenic mobility.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2022)
Article
Materials Science, Ceramics
Yas Al-Hadeethi, A. Al-Mujtabi, Fahd M. Al-Marzouki, Alaa Y. Mahmoud, Ahmad Umar, A. M. Abdel-Daiem, Mohammad Shahnawaze Ansari
Summary: In this study, the deposition parameters of SU8 2000.5 photoresists were investigated and optimized for photolithography, leading to the fabrication of V-shaped groove diffraction gratings. The optimized process conditions allowed for the successful creation of well-defined V-shaped grooves on a silicon substrate.
CERAMICS INTERNATIONAL
(2021)
Article
Engineering, Multidisciplinary
Xaver Klemenschits, Siegfried Selberherr, Lado Filipovic
Summary: TCAD is essential for the semiconductor industry, but the accuracy of current emulation models is limited by their reliance on explicit surface representations. A novel geometric advection algorithm combines the advantages of explicit and implicit surface representations, providing a new way of simulating microelectronic fabrication processes with high computational efficiency.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2021)
Article
Energy & Fuels
Jeong Eun Park, Chang-Soon Han, Won Seok Choi, Donggun Lim
Summary: In this study, pyramid structures of various sizes were formed on wafers through different etching processes to analyze their effects on solar cell characteristics. It was found that the micro-sized pyramid-structured wafers exhibited higher quantum efficiency in the short wavelength region compared to nano-sized pyramid-structured wafers.
Article
Materials Science, Multidisciplinary
Xinyi Cao, Yibo Xiao, Qiao Dong, Shaobo Zhang, Junzhuan Wang, Lianhui Wang, Li Gao
Summary: This study reports a low-cost and large-area fabrication method for metasurfaces through a combination of soft nanoimprint lithography and reactive ion etching. The size of meta-atoms can be tuned by controlling the etching condition carefully and implementing an iterative imprint and etch process. This approach is effective for wafer-scale nanophotonics, allowing for alteration of metasurface resonances and replication of new structures with minimum cost.
ADVANCED PHOTONICS RESEARCH
(2022)
Article
Instruments & Instrumentation
Naoyoshi Hirade, Hiromitsu Takahashi, Nagomi Uchida, Masanori Ohno, Kento Torigoe, Yasushi Fukazawa, Tsunefumi Mizuno, Hiroto Matake, Kengo Hirose, Syouhei Hisadomi, Kazuhiro Nakazawa, Kazutaka Yamaoka, Norbert Werner, Jakub Ripa, Satoshi Hatori, Kyo Kume, Satoshi Mizushima
Summary: The research investigated the radiation damage effects of two new types of MPPC under a proton beam, showing that one model was less degraded and may exhibit decreases in dark current and threshold energy after irradiation, while the threshold energy of one model did not significantly decrease in environments below 0 degrees Celsius.
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT
(2021)