Article
Engineering, Electrical & Electronic
Jinzhu Zhou, Weijian Zhou, Yue Zhang, Yipeng Wang, Tieying Ma
Summary: Si-based double-layer overlapping open microchannels have been designed and fabricated for microfluidic applications. The top channel has been ingeniously designed in both T-shaped and X-shaped configurations along the <100> direction, while the bottom channel has been prepared along the <110> direction, allowing it to be semi-buried into the top channel at a 45-degree angle. An undercut characteristic of 25% TMAH has been utilized to create a unique overlapping microchannel structure by removing material from the overlapping part of the two layers of channels. This results in intersecting microchannels that are not connected, providing significant structural advantages over traditional single-layer microchannels. With this innovative design, two different substances can be delivered independently and efficiently in the same area.
SENSORS AND ACTUATORS A-PHYSICAL
(2023)
Article
Chemistry, Analytical
Yipeng Wang, Weijian Zhou, Tieying Ma
Summary: A four-step etching method was used to prepare a double-layer cross Si microchannel structure, with the morphology of the channels being controlled by varying the direction and time of etching. The double-layer crossed microchannels have potential applications in microfluidic technology and microchannel heat dissipation technology.
Article
Engineering, Electrical & Electronic
S. Purohit, V Swarnalatha, A. K. Pandey, R. K. Sharma, P. Pal
Summary: This research investigates the etching characteristics of Si{110} in 10 M sodium hydroxide with and without the addition of hydroxylamine (NH2OH). The incorporation of NH2OH significantly improves the etch rate and the corner undercutting. The findings are useful for scientists and engineers in the fabrication of MEMS structures using wet anisotropic etching and have the potential to promote the application of wet etching in MEMS.
JOURNAL OF MICROMECHANICS AND MICROENGINEERING
(2022)
Article
Nanoscience & Nanotechnology
Lei Wu, Licong Cui, Wang He, Jian Guo, Bingjun Yu, Linmao Qian
Summary: This study systematically investigates the roles of mechanically driven defects in wet etching and reveals the antietching role of mechanically driven amorphous Si (a-Si) and the promoting etching role of distorted Si. Selective etching mechanisms for each defect are addressed based on the proposed dissolution model.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Chemistry, Multidisciplinary
Christopher Schutzeichel, Nataliya Kiriy, Anton Kiriy, Brigitte Voit
Summary: This paper presents a novel microstructuring method that allows patterning of n-doped silicon substrates without the need for etch-masks or stencils. The method involves simple alkaline etching under illumination, controlled by p-doped micro-sized implants buried beneath the n-doped layer. The buried implants act as micro-sized photovoltaic cells, generating a flux of electrons to protect the silicon oxide layer from etching, ultimately leading to substrate microstructuring.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Chemistry, Physical
Valeria Lotito, Tomaso Zambelli
Summary: Monolayers of self-assembled quasi-spherical colloidal particles are crucial in materials science and engineering. They serve as templates for nanostructure fabrication or are incorporated in final structures for their intrinsic properties. Various methods have been developed to modify the size and shape of colloidal particles, with dry etching being a widely used technique. Such particles can be utilized for patterning or suspended in solvents for diverse applications.
ADVANCES IN COLLOID AND INTERFACE SCIENCE
(2022)
Article
Chemistry, Multidisciplinary
Jeong-Sik Jo, Jihoon Choi, Seung-Hoon Lee, Changhoon Song, Heeso Noh, Jae-Won Jang
Summary: The mass fabrication of 3D silicon microstructures with a 100 nm resolution is achieved using scanning probe lithography combined with metal-assisted chemical etching. Various protruding and recessed silicon structures are obtained via different lithography methods, demonstrating applications in nanoimprinting and PDMS stamps. Mass production of arbitrarily shaped silicon microparticles at submicrometer resolution is developed using silicon-on-insulator substrates, with applications in optical microresonators, surface-enhanced Raman scattering templates, and smart microparticles for fluorescence signal coding.
Article
Optics
Shipeng Zhou, Xiaowei Li, Ji Huang, Zhipeng Wang, Yang Liu, Shuai Gao, Zhijie Xu, Lan Jiang
Summary: A flexible, facile, and mask-free method is reported for fabricating nanogap structures with controllable size on silicon using a near-infrared femtosecond laser. The method involves spatially shaped femtosecond laser single-pulse modification assisted with chemical etching, resulting in two types of nanogap structures with small feature sizes.
Article
Chemistry, Analytical
Quanquan Sun, Jiaxuan Tang, Lifeng Shen, Jie Lan, Zhenfeng Shen, Junfeng Xiao, Xiao Chen, Jianguo Zhang, Yu Wu, Jianfeng Xu, Xuefang Wang
Summary: This paper proposes a high-precision, low-cost method for processing spherical microlens arrays using a nanoimprint technique. By fabricating a nanoimprint mold with high surface precision and low surface roughness, and performing anti-sticking treatment on the mold, the microstructure of the microlens array was successfully transferred to a silicon substrate.
Article
Materials Science, Multidisciplinary
Shahnawaz Uddin, Md Roslan Hashim, Mohd Zamir Pakhuruddin
Summary: This study investigated the fabrication of b-Si absorber using the AACE process for the first time, and found that b-Si fabricated with a 12 nm thick aluminum film exhibited the lowest Ravg and highest broadband light absorption. The findings demonstrate the potential of the AACE process for producing b-Si with superior broadband light absorption, which is important for photovoltaic applications.
MATERIALS CHEMISTRY AND PHYSICS
(2021)
Article
Electrochemistry
B. Hamelin, J. Yang, F. Ayazi
Summary: Integrated mechanical resonators made in high acoustic velocity materials with high quality factors (Q) are crucial for various applications. Silicon is commonly used for MEMS resonators, but SiC has low phononic dissipation. This paper presents the latest developments in precision DRIE of monocrystalline SiC-on-Insulator substrates to leverage the mechanical properties of SiC, achieving Q products beyond 1 x 10^14 Hz. Surface roughness impact on dissipation and etching of mirror-polished trenches in SiCOI substrates are discussed, aiming for monocrystalline SiC resonators with Qs beyond 100 million.
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
(2021)
Article
Pharmacology & Pharmacy
Conor O'Mahony, Ryan Sebastian, Fjodors Tjulkins, Derek Whelan, Andrea Bocchino, Yuan Hu, Joe O'Brien, Jim Scully, Margaret Hegarty, Alan Blake, Ines Slimi, A. James P. Clover, Alexander Lyness, Anne-Marie Kelleher
Summary: This paper describes a method for fabricating arrays of hollow silicon microneedles using only two bulk silicon etches. The microneedle arrays show biomechanical reliability and have the potential to be used for transdermal delivery and diagnostics.
INTERNATIONAL JOURNAL OF PHARMACEUTICS
(2023)
Article
Pharmacology & Pharmacy
Olivia Howells, Gareth J. Blayney, Benedetta Gualeni, James C. Birchall, Pey F. Eng, Huma Ashraf, Sanjiv Sharma, Owen J. Guy
Summary: This study presents the fabrication of silicon in-plane microneedle arrays using a simple single wet etch step. The method utilizes KOH etching to create solid and hollow microneedles with different geometries for effective drug delivery. The microneedle arrays effectively penetrate the skin and can be used for delivery of active ingredients. The fabrication method is simple, scalable, and cost-effective, allowing the production of microneedles with variable lengths.
EUROPEAN JOURNAL OF PHARMACEUTICS AND BIOPHARMACEUTICS
(2022)
Article
Engineering, Electrical & Electronic
Lia Aprilia, Tatsuya Meguro, Ratno Nuryadi, Tetsuo Tabei, Hidenori Mimura, Shin-Ichiro Kuroki
Summary: In this study, the anisotropic etching release of a silicon micro-cantilever structure with embedded metal layers was achieved by utilizing a Mo mask and the anisotropic wet silicon etching method. The Mo mask was employed to protect the metal resistor during the silicon etching process, resulting in successful release of the cantilever structure. This method offers the advantages of no backside alignment masks, relatively low temperature, and compatibility with CMOS for chemical and bio-sensor applications.
JOURNAL OF MICROELECTROMECHANICAL SYSTEMS
(2023)
Article
Engineering, Electrical & Electronic
Tzu-Chieh Hong, Wen-Hsiang Lu, Yeong-Her Wang, Jiun-Yun Li, Yao-Jen Lee, Tien-Sheng Chao
Summary: Germanium-tin (GeSn) epitaxy layer was grown on an 8-inch SOI wafer with a Ge buffer layer. The etching rates of different solutions for the GeSn layer were investigated. The developed two-step etching process allows the selective etching of the Ge buffer and Si bottom layers, facilitating the fabrication of GeSn nanowires (NWs). GeSn NWFETs were successfully fabricated and the strain of the GeSn NW channels was preserved using the proposed optimized fabrication process.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Engineering, Electrical & Electronic
Akarapu Ashok, Rohit Prakash Nighot, Nagesh Kumar Sahu, Prem Pal, Ashok Kumar Pandey
MICROSYSTEM TECHNOLOGIES-MICRO-AND NANOSYSTEMS-INFORMATION STORAGE AND PROCESSING SYSTEMS
(2019)
Article
Materials Science, Multidisciplinary
Aparna Gangele, Akarapu Ashok, Chandra Sekhar Sharma, Prem Pal, Ashok Kumar Pandey
MATERIALS RESEARCH EXPRESS
(2019)
Article
Nanoscience & Nanotechnology
Veerla Swarnalatha, Prem Pal, Ashok Kumar Pandey, Avvaru Venkata Narasimha Rao, Yan Xing, Hiroshi Tanaka, Kazuo Sato
MICRO & NANO LETTERS
(2020)
Article
Nanoscience & Nanotechnology
Parappurath Krishna Menon, Avvaru Venkata Narasimha Rao, Airpula Linga Murthy, Ashok Kumar Pandey, Prem Pal
MICRO & NANO LETTERS
(2020)
Article
Physics, Applied
Ashok Akarapu, Rohit Prakash Nighot, Lalsingh Devsoth, Mukul Yadav, Prem Pal, Ashok Kumar Pandey
PHYSICAL REVIEW APPLIED
(2020)
Article
Engineering, Electrical & Electronic
P. Krishna Menon, Akarapu Ashok, A. V. Narasimha Rao, Ashok Kumar Pandey, Prem Pal
MICROELECTRONIC ENGINEERING
(2020)
Article
Engineering, Electrical & Electronic
Arnab Biswas, Vishal S. Pawar, P. Krishna Menon, Prem Pal, Ashok Kumar Pandey
Summary: The fabrication of high aspect ratio MEMS structures like comb drive structures are mostly done through the Deep Reactive Ion Etching (DRIE) process, with the Bosch process being a popular method within DRIE. Despite the expectation of straight and smooth walls from the alternating etching and passivation processes, surface undulations known as scalloping are often present, affecting the performance of MEMS devices. This study focuses on the impact of defects such as slanting and scalloping on a MEMS vibratory gyroscope, providing insights for designing MEMS devices with improved performance.
MICROSYSTEM TECHNOLOGIES-MICRO-AND NANOSYSTEMS-INFORMATION STORAGE AND PROCESSING SYSTEMS
(2021)
Article
Materials Science, Multidisciplinary
M. L. V. Mahesh, Prem Pal, V. V. Bhanu Prasad, A. R. James
CURRENT APPLIED PHYSICS
(2020)
Article
Engineering, Electrical & Electronic
S. Purohit, V Swarnalatha, A. K. Pandey, R. K. Sharma, P. Pal
Summary: This research investigates the etching characteristics of Si{110} in 10 M sodium hydroxide with and without the addition of hydroxylamine (NH2OH). The incorporation of NH2OH significantly improves the etch rate and the corner undercutting. The findings are useful for scientists and engineers in the fabrication of MEMS structures using wet anisotropic etching and have the potential to promote the application of wet etching in MEMS.
JOURNAL OF MICROMECHANICS AND MICROENGINEERING
(2022)
Article
Nanoscience & Nanotechnology
S. Purohit, V. Swarnalatha, A. K. Pandey, P. Pal
Summary: This paper reports the wet anisotropic etching characteristics of Si{111} in sodium hydroxide (NaOH) with and without the addition of hydroxylamine (NH2OH). The effect of NH2OH on the etch rate, etched surface roughness and morphology, and undercutting at mask edges aligned along < 112 > direction is investigated. It is found that the incorporation of NH2OH significantly enhances the etch rate and the undercutting at mask edges that do not consist of {111} planes.
MICRO AND NANO SYSTEMS LETTERS
(2022)
Article
Nanoscience & Nanotechnology
V. Swarnalatha, S. Purohit, P. Pal, R. K. Sharma
Summary: This study investigates the etching characteristics of a non-conventional etchant, hydroxylamine (NH2OH) added sodium hydroxide (NaOH) solution, on Si{100} wafer. The addition of NH2OH significantly improves the etching rate, surface morphology, and undercutting at convex corners. These findings are of great importance for engineering applications.
MICRO AND NANO SYSTEMS LETTERS
(2022)
Review
Nanoscience & Nanotechnology
Prem Pal, Veerla Swarnalatha, Avvaru Venkata Narasimha Rao, Ashok Kumar Pandey, Hiroshi Tanaka, Kazuo Sato
Summary: Wet anisotropic etching is widely employed in silicon bulk micromachining for fabricating microstructures in MEMS and improving the efficiency of crystalline silicon solar cells by reducing light reflectance. The etch rate, affected by factors such as temperature and additives, is crucial in MEMS industry for faster fabrication. Various methods, including physical agitation and chemical additives, have been proposed to increase the etch rate of silicon.
MICRO AND NANO SYSTEMS LETTERS
(2021)
Article
Nanoscience & Nanotechnology
Arti Gupta, Prem Pal, Chandra Shekhar Sharma
MICRO & NANO LETTERS
(2020)
Article
Materials Science, Multidisciplinary
Avvaru Venkata Narasimha Rao, Prem Pal, Ashok Kumar Pandey, Veerla Swarnalatha, P. Krishna Menon, Hiroshi Tanaka, Kazuo Sato
ECS JOURNAL OF SOLID STATE SCIENCE AND TECHNOLOGY
(2019)
Article
Materials Science, Multidisciplinary
Arti Gupta, Prem Pal, Chandra Shekhar Sharma
ECS JOURNAL OF SOLID STATE SCIENCE AND TECHNOLOGY
(2019)