Article
Materials Science, Multidisciplinary
Julia Bondareva, Ekaterina Timofeeva, Alexandr Anikanov, Maxim Krasilnikov, Maxim Shibalov, Vasily Sen, Alexander Mumlyakov, Stanislav Evlashin, Mikhail Tarkhov
Summary: The use of scandium as a hard mask material enables high-resolution wet etching in microelectronics and photovoltaic applications, opening up possibilities for creating different microscale topographical patterns.
Article
Nanoscience & Nanotechnology
Elif Bilgilisoy, Jo-Chi Yu, Christian Preischl, Lisa McElwee-White, Hans-Peter Steinrueck, Hubertus Marbach
Summary: The precise deposition of nanoscaled structures is crucial for nanomaterial applications. This study successfully fabricated clean and well-defined Ru nanomaterials using highly focused electron beam-induced deposition. The study found that the deposition process competed with the electron-induced etching, resulting in lower Ru content initially. However, with increasing electron doses, the Ru content increased and the etching process became less pronounced. This research expands the possibilities of engineering nanostructured materials.
ACS APPLIED NANO MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Subrata Mandal, Chirantan Das, Subhrajit Sikdar, Basudev Nag Chowdhury, Pintu Singha, Aritra Banerjee, Anupam Karmakar, Sanatan Chattopadhyay
Summary: In this study, a substrate engineered patterned array of square-shaped features of size 1.5 μm x 1.5 μm, comprising of <111>/[100]-planes of p-Si substrate, was successfully developed using electron beam lithography assisted selective anisotropic wet etching. The exposed <111>/[100]-planes were confirmed by FESEM imaging and X-ray diffraction study. The surface engineered Si-substrates have potential applications in electronic, optoelectronic, and bio-sensing devices.
MATERIALS CHEMISTRY AND PHYSICS
(2022)
Article
Chemistry, Physical
Pawel Kozlowski, Krzysztof Czuba, Krzysztof Chmielewski, Jacek Ratajczak, Joanna Branas, Adam Korczyc, Kazimierz Reginski, Agata Jasik
Summary: The paper investigates several aspects of the fabrication technology of micrometer-sized indium bumps with a smooth surface morphology, achieved through optimized thermal evaporation to achieve 8 μm-thick layers. A reliable, repeatable, simple, and quick approach to indium bump fabrication was developed through a series of experiments, along with a technique to prevent oxidation inside the In columns.
Article
Materials Science, Multidisciplinary
Peter Panjan, Aljaz Drnovsek, Nastja Mahne, Miha Cekada, Matjaz Panjan
Summary: This study investigates and compares the surface topography of hard coatings deposited by three different physical vapor deposition methods, summarizing the expertise gained during the development of PVD hard coatings for tool and machine component protection. Variations in surface topography between deposition techniques, the impact of ion etching on surface cleaning, and the causes of surface roughness in PVD coatings are discussed.
Article
Computer Science, Information Systems
Zheng Jiang, Hao Zhu, Qingqing Sun, Davidwei Zhang
Summary: The study improved and optimized the ACHM film processing process through comparative research of C2H2 and C3H6 precursors at different temperatures, achieving better step coverage. Experimental results showed that increasing power, temperature, C2H2 flow, and adjusting gap, pressure, and carrier gas flow can enhance dry etching performance. Selective etching ratio of SiO2 and SiN was obtained along with an improved process window.
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
Habib Ahmad, Zachary Engel, Muneeb Zia, Alex S. Weidenbach, Christopher M. Matthews, Bill Zivasatienraj, Muhannad S. Bakir, W. Alan Doolittle
Summary: A highly selective cascaded Ni hard mask was developed, suitable for the formation of deep vertical mesas for high-power devices, achieving high selectivity and undamaged GaN surface morphology. Different methods of applying patterned Ni hard masks were studied for their effects on GaN etch rate and selectivity, with the cascaded Ni hard mask method reaching 100% yield.
SEMICONDUCTOR SCIENCE AND TECHNOLOGY
(2021)
Article
Chemistry, Physical
Shuo Zhang, Gediminas Gervinskas, Yang Liu, Ross K. W. Marceau, Jing Fu
Summary: This study explores the application of nanoscale in-situ cryo-condensation coating technique on needle-shaped specimens and frozen hydrated cells. By controlling parameters, the properties of the deposited layer can be tuned, revealing surface morphologies and investigating the physical mechanisms of curing. This approach opens a novel route to nanofabrication on tip geometry and site-specific conductive protection.
APPLIED SURFACE SCIENCE
(2021)
Article
Materials Science, Multidisciplinary
Yanli Li, Weier Lu, Shanfeng Wang, Qingxi Yuan, Xiangdong Kong, Li Han, Yang Xia
Summary: In this study, atomic layer deposition (ALD) and focused ion beam (FIB) milling were used to prepare multilayer Fresnel zone plate (ML-FZP) for hard X-ray microscopy. The obtained Al2O3/HfO2 ML-FZP had a total zone thickness of 10 μm, which is much greater than the reported ML-FZPs fabricated by the same method, and is of great significance to increase the active region of FZP. The ML-FZP with an outermost zone width of 40 nm and aspect ratio of 157 achieved a 29 nm half-pitch cut-off resolution in transmission X-ray microscopy (TXM) at 9 keV.
Article
Chemistry, Multidisciplinary
Lu Xie, Huilong Zhu, Yongkui Zhang, Xuezheng Ai, Junjie Li, Guilei Wang, Anyan Du, Zhenzhen Kong, Qi Wang, Shunshun Lu, Chen Li, Yangyang Li, Weixing Huang, Henry H. Radamson
Summary: A dual-selective atomic layer etching technique has been developed to control the etch rate and size of Ge nanowires in vGAAFETs, considering the selectivity between Ge0.8Si0.2 and Ge. Experimental results demonstrate that the etch rate and selectivity of Ge vary with different nitric acid temperatures.
Article
Engineering, Electrical & Electronic
Medhat Samaan, Huseyin Ekinci, Ripon Dey, Xiaoli Zhu, Dmitry Pushin, Bo Cui
Summary: This paper introduces a simple method to convert commercially available standard AFM probes to HAR probes using FIB and plasma etching techniques. Compared to traditional HAR probe fabrication methods, this method significantly reduces the usage of FIB and is suitable for batch production.
MICROELECTRONIC ENGINEERING
(2023)
Article
Materials Science, Multidisciplinary
Mason Adshead, Maddison Coke, Gianfranco Aresta, Allen Bellew, Matija Lagator, Kexue Li, Yi Cui, Rongsheng Cai, Abdulwahab Almutawa, Sarah J. Haigh, Katie Moore, Nicholas Lockyer, Christopher M. Gourlay, Richard J. Curry
Summary: A platform called P-NAME for nanoscale advanced materials engineering is introduced, which includes a high-resolution focused ion beam system, a scanning electron microscope, and a secondary electron detector. The system demonstrates the capability of isotopic mass-resolution for various ion species that are important for nanomaterials engineering and nanofunctionalization. The performance of the system is validated using secondary ion mass spectrometry, and other capabilities such as sub-10 nm ion beam imaging resolution, direct-write ion beam doping, and nanoscale ion lithography are also showcased.
ADVANCED ENGINEERING MATERIALS
(2023)
Article
Optics
Yunpeng Ren, Li Cheng, Xincheng Tu, Kun He, Yunxia Ye, Yufeng Tao, Xudong Ren
Summary: This paper proposes a picosecond laser modification assisted wet etching technology to prepare the quartz pendulous reed, which is the core part of the quartz flexible accelerometer. The modification mechanism of fused silica induced by picosecond laser was investigated, and the mapping among etching time, etching temperature, and HF solution concentration was studied. The proposed technology has the advantages of high dimensional accuracy, good edge quality, low residual stress, and high efficiency.
OPTICS AND LASER TECHNOLOGY
(2023)
Article
Chemistry, Multidisciplinary
Minho Choi, Seongmoon Jun, Kie Young Woo, Hyun Gyu Song, Hwan-Seop Yeo, Sunghan Choi, Doyoun Park, Chung-Hyun Park, Yong-Hoon Cho
Summary: This paper introduces a nanoscale focus pinspot (NFP) technique to improve the single-photon purity of QDs, enabling QDs to exhibit better single-photon properties at higher temperatures. The NFP technique is nondestructive, preserving the physical structure and photonic functions of QDs, showing promising potential for various high-purity quantum emitters.
Article
Chemistry, Multidisciplinary
Saba Ghafourisaleh, Marko Vehkamaki, Anton Vihervaara, Chao Zhang, Mikko J. Heikkila, Markku Leskela, Matti Putkonen, Mikko Ritala
Summary: This paper reports the deposition of pyrrone thin film materials using molecular layer deposition (MLD) with pyromellitic dianhydride (PMDA) and 3,3'-diaminobenzidine (DAB) as monomers and ozone as a promoter. Various precursor pulsing sequences are tested, resulting in different growth rates of the films. The films exhibit stability and withstand high temperatures when annealed in air.
ADVANCED MATERIALS INTERFACES
(2023)
Article
Chemistry, Multidisciplinary
Alexander Weiss, Jacqueline Goldmann, Sakari Kettunen, Georgi Popov, Tomi Iivonen, Miika Mattinen, Pasi Jalkanen, Timo Hatanpaa, Markku Leskela, Mikko Ritala, Marianna Kemell
Summary: This study demonstrates a scalable and conformal deposition of copper iodide (CuI) thin films using atomic layer deposition (ALD). The two-step ALD process, involving deposition of CuO and subsequent conversion to CuI using HI vapor, results in phase-pure, uniform, and high-purity CuI films. The successful deposition of CuI on various substrates and its application in diode structures and perovskite solar cells suggests that the ALD-based approach offers a viable alternative for depositing transparent conductive p-type CuI thin films in complex high aspect ratio structures and large substrate areas.
ADVANCED MATERIALS INTERFACES
(2023)
Article
Materials Science, Coatings & Films
Heta-Elisa Nieminen, Mykhailo Chundak, Mikko J. Heikkila, Paloma Ruiz Karkkainen, Marko Vehkamaki, Matti Putkonen, Mikko Ritala
Summary: This paper introduces a vacuum cluster tool specifically designed for studying reaction mechanisms in atomic layer deposition (ALD) and atomic layer etching (ALE) processes. The tool connects a commercial flow-type ALD reactor to a set of UHV chambers, allowing versatile surface characterization without breaking the vacuum environment. The tool enables the study of surface composition and reaction intermediates formed during precursor or etchant pulses in conditions close to true ALD and ALE processing.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2023)
Article
Biochemistry & Molecular Biology
Elina Kylmaoja, Faleh Abushahba, Jani Holopainen, Mikko Ritala, Juha Tuukkanen
Summary: Coating bone implants with hydroxyapatite (HA) has benefits for osseointegration, but there may be differences in monocyte differentiation and material resorption compared to natural bone. In this study, ALD-HA coating on a titanium substrate was compared with bovine bone, and it was found that ALD-HA led to the presence of non-resorbing cells instead of resorbing osteoclasts. The topographical properties of ALD-HA, such as surface roughness, may play a role in this cellular reaction.
Article
Chemistry, Multidisciplinary
Xinzhi Li, Marko Vehkamaki, Mykhailo Chundak, Kenichiro Mizohata, Anton Vihervaara, Markku Leskela, Matti Putkonen, Mikko Ritala
Summary: This paper presents the preparation process and characterization of boron-doped Al2O3 thin films using atomic layer deposition. The effects of deposition temperature and annealing process on the properties of the films are investigated. The boron-doped Al2O3 film deposited at 200 degrees C shows low leakage current and a dielectric constant of 5.18 when the film thickness is 70 nm.
ADVANCED MATERIALS INTERFACES
(2023)
Article
Engineering, Environmental
Johanna Paajanen, Lauri Pettila, Satu Lonnrot, Mikko Heikkila, Timo Hatanpa, Mikko Ritala, Risto Koivula
Summary: Nuclear power is a clean energy source, but it produces hazardous fission products such as 90Sr. Researchers have developed submicron TiO2 and TiO2/SiO2 composite fibers to remove Sr2+ from water. These fibers showed excellent Sr2+ adsorption capacity, and the hydrothermally modified TiO2 fibers had the highest distribution coefficient. The nanorods on the fibers also remained undamaged in column operation tests, making them promising for industrial wastewater treatment.
CHEMICAL ENGINEERING JOURNAL ADVANCES
(2023)
Article
Chemistry, Physical
Alexander Weiss, Mariia Terletskaia, Georgi Popov, Kenichiro Mizohata, Markku Leskela, Mikko Ritala, Marianna Kemell
Summary: This study addresses the limited ability to deposit conformal and scalable halide perovskite thin films by using atomic layer deposition (ALD). Two new ALD processes, SnI2 and CsSnI3, are presented in order to achieve lead-free and environmentally friendly absorber layers for perovskite solar cells (PSCs). The findings demonstrate the successful deposition of phase-pure gamma-CsSnI3 films through conversion reactions and propose an alternative method using pulsed chemical vapor deposition (pulsed CVD) SnI2 step.
CHEMISTRY OF MATERIALS
(2023)
Article
Chemistry, Physical
Valtteri Lasonen, Anton Vihervaara, Georgi Popov, Eva Tois, Lars Mester, Mohammad Karimi, Yoana Ilarionova, Reza Jafari Jam, Jonas Sundqvist, Mikko Ritala
Summary: Area-selective etching (ASE) of polymers is a novel and simple self-aligned patterning technique with potential application in semiconductor device fabrication. The polymer film is selectively decomposed on top of catalytically active materials while staying intact on catalytically inactive materials, eliminating edge placement errors and defects. This study investigates the ASE of poly(methyl methacrylate) (PMMA) using various catalytic materials in different atmospheres. The feasibility of the entire patterning process is demonstrated on a 100 nanometer scale.
CHEMISTRY OF MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
Xinzhi Li, Marko Vehkamaki, Mykhailo Chundak, Kenichiro Mizohata, Anton Vihervaara, Matti Putkonen, Markku Leskela, Mikko Ritala
Summary: This article presents a study on a new type of inorganic-organic silicon-based molecular layer deposition (MLD) process, using AlCl3 and BTEB as precursors. The researchers successfully deposited hybrid films with high growth per cycle (GPC). FESEM and AFM were used to analyze the surface morphology of the films, while ATR-FTIR, ToF-ERDA, and XPS were employed to analyze the structure and composition. The storage environment of the films was found to significantly affect their performance.
ADVANCED COMPOSITES AND HYBRID MATERIALS
(2023)
Article
Chemistry, Inorganic & Nuclear
Elisa Atosuo, Miia Maentymaeki, Leevi Pesonen, Kenichiro Mizohata, Timo Hatanpaa, Markku Leskelae, Mikko Ritala
Summary: The present study investigates the atomic layer deposition (ALD) of CoF2, NiF2, and HoF3 thin films. CoF2 deposition was achieved using CoCl2(TMEDA) and NH4F as precursors, resulting in tetragonal CoF2 films with a growth per cycle (GPC) of 0.7-1.2 Å. NiF2 deposition utilized Ni(thd)(2) and TaF5 or NbF5 as precursors, producing tetragonal NiF2 films with high oxygen and hydrogen contents. HoF3 films were deposited using Ho(thd)(3) and NbF5 as precursors, yielding orthorhombic HoF3 films with low impurity contents.
DALTON TRANSACTIONS
(2023)
Article
Chemistry, Inorganic & Nuclear
Chao Zhang, Marko Vehkamaki, Markku Leskela, Mikko Ritala
Summary: Atomic layer deposition (ALD) of ZnS using elemental zinc and sulfur as precursors demonstrates excellent inherent selectivity on Ti and TiO2 surfaces, but no growth is observed on native SiO2 and Al2O3 surfaces. The growth rate on Ti remains constant at 1.0Å per cycle at temperatures of 400-500°C, while on TiO2, the growth rate increases significantly. The selective adsorption of sulfur on TiO2 over Al2O3 and SiO2 is assumed to be the selectivity mechanism.
DALTON TRANSACTIONS
(2023)
Article
Chemistry, Physical
Anton Vihervaara, Timo Hatanpaa, Heta-Elisa Nieminen, Kenichiro Mizohata, Mykhailo Chundak, Mikko Ritala
Summary: In this study, high purity gold films were successfully deposited on various substrate materials for the first time using thermal reductive atomic layer deposition method. The precursors used were AuCl-(PEt3) and 1,4-bis-(trimethylgermyl)-1,4-dihydropyrazine. The growth rate was measured to be 1.7 angstroms per cycle after full coverage of the film. The films exhibited low resistivity close to the bulk value and minimal impurity content. The reaction mechanism of the process was studied in situ using a quartz crystal microbalance and a quadrupole mass spectrometer.
