Journal articles: 'Etching'

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Çakır, Orhan. "Study of Etch Rate and Surface Roughness in Chemical Etching of Stainless Steel." Key Engineering Materials 364-366 (December 2007): 837–42. http://dx.doi.org/10.4028/www.scientific.net/kem.364-366.837.

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In this study, stainless steel material (X5CrNi1810) was micromachined by chemical etching method. Ferric chloride was selected as etchant which is the most widely used etchant for iron-based materials. Four different etchant concentrations (32 °Bé, 36 °Bé, 40 °Bé and 44 °Bé) were used at various etching temperature. Moreover, the influence of the addition of hydrochloric acid to main etchant on etching performance was examined. The aim of this study was to investigate the depth of etch and surface roughness affected by etchant concentration, hydrochloric acid addition and etching temperature. It was observed that etching temperature for any etchant concentration is important factor in case of depth of etch and surface roughness. It was also noticed that the addition of hydrochloric acid to main etchant increased depth of etch value at any etching temperature. The optimum etching parameters were obtained for the chemical etching of stainless steel.

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Chabanon, Angélique, Alexandre Michau, Michel Léon Schlegel, Deniz C. Gündüz, Beatriz Puga, Frédéric Miserque, Frédéric Schuster, et al. "Surface Modification of 304L Stainless Steel and Interface Engineering by HiPIMS Pre-Treatment." Coatings 12, no. 6 (May 25, 2022): 727. http://dx.doi.org/10.3390/coatings12060727.

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A clean and defect-free substrate/coating interface is required to guarantee good adhesion of coatings under service conditions. For this purpose, an etching pre-treatment using High-Power Impulse Magnetron Sputtering (HiPIMS) was performed to modify the surface of 304L stainless steel. The effect of three etching procedures on the substrate properties, such as corrosion resistance and adhesion, was investigated with unprecedented spatial resolution and spectroscopic details. Glancing angle X-ray diffraction showed modification in phase content but no neoformation after steel etching. X-ray photoelectron spectroscopy confirmed the presence of etchant species (6–7 at.%) on the extreme surface of the substrate. Transmission Electron Microscopy and Atomic Probe Tomography showed that the interface was less than a few nanometers wide. Polarization curves in a nitric acid solution at boiling temperature showed, for the first time, that the Ti+ and Zr+ etchings decreased the corrosion current density compared to the untreated original surface. Scratch-test measurements indicated better substrate/coating adhesion using HiPIMS metal ion etching. Electrochemical characterization revealed that Zr etching and thin coating improve the anti-corrosion properties of stainless steel in strong nitric acid conditions.

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Hvozdiyevskyi, Ye Ye, R. O. Denysyuk, V. M. Tomashyk, G. P. Malanych, Z. F. Tomashyk Tomashyk, and A. A. Korchovyi. "Chemical-mechanical polishing of CdTe and based on its solid solutions single crystals using HNO3 + НІ + ethylene glycol iodine-emerging solutions." Chernivtsi University Scientific Herald. Chemistry, no. 819 (2019): 45–49. http://dx.doi.org/10.31861/chem-2019-819-07.

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The interaction of the CdTe and Zn0.04Cd0.96Te, Cd0.2Hg0.8Te solid solutions single crystals with the iodine-emerging etchings based on aqueous solutions of HNO3 + НІ + ethylene glycol has been investigated and etching compositions have been developed and optimized, as well as methods of their chemical treatment for the formation of high-quality surface. The dissolution of these semiconductor materials in the aqueous solutions of the (HNO3+HI+EG)/EG have been investigated and dependences “etchant composition – etching rate” with determining the regions of polishing and unpolishing solutions have been constructed. It was found that the semiconductors etching rate (chemical-mechanical polishing) decreases from 73.2 to 0.5 μm/min and the polishing features of the HNO3+HI+EG etching composition improve when the EG content is increasing. The minimum value of the etching rates is achieved when the saturation of the organic component is maximum (95 vol. %). The dependences of the chemical-mechanical polishing rate on the dilution of the base polishing etchant with ethylene glycol and the surface condition after polishing have investigated using metallographic analysis and atomic force microscopy. It was established that chemical-mechanical polishing of the CdTe and Zn0.04Cd0.96Te, Cd0.2Hg0.8Te solid solutions single crystals by the (HNO3+HI+EG)/EG solutions promote decreasing of the structural damages of the substrate and obtaining the high-quality polishing surface. It has been shown that etchant compositions of HNO3+HI+ EG with EG as a solvent completely meet the requirements for CMP etchants. Treatment of the Cd0.2Hg0.8Te crystal surfaces with new etchant mixtures allows to obtain ultra-smooth surfaces Ra = 1.5 nm. The polishing etchant compositions (HNO3+HI+EG)/EG and technological procedures of the chemical mechanical polishing for the disturbed layer elimination, controlled thinning of the plates up to reference dimension, as well as the thin layers removing and CdTe single crystals and Zn0.04Cd0.96Te, Cd0.2Hg0.8Te solid solutions finishing polishing have been optimized.

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Li, Hao, Yong You Geng, and Yi Qun Wu. "Selective Wet Etching Characteristics of Aginsbte Phase Change Film with Ammonium Sulfide Solution." Advanced Materials Research 529 (June 2012): 388–93. http://dx.doi.org/10.4028/www.scientific.net/amr.529.388.

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The selective wet etching characteristics of AgInSbTe film as a new thermal lithography material were studied with ammonium sulfide solution as etchant. Influences of vacuum-annealing temperature, etchant concentration and wet etching time on selective wet etching characteristics of the amorphous and crystalline AgInSbTe films were investigated. Experimental results indicated that the etching rate of AgInSbTe film increased with the enhancement of crystallization extent, and the etching rate of crystalline state AgInSbTe film annealed at 300°C was 35nm/min in 17wt% ammonium sulfide solution, about 17.5 times as high as that of the amorphous state. Moreover, a good surface morphology of AgInSbTe film with roughness of less than 3 nm was attained in the area of 10×10 μm2 after wet-etching. The wet etching selectivity of the AgInSbTe film was strongly influenced by the annealing temperature and the etchant concentration.

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Pashchenko, G. A., M. J. Kravetsky, and O. V. Fomin. "Singularities of Polishing Substrates GaAs by Chemo-Dynamical and Non-Contact Chemo-Mechanical Methods." Фізика і хімія твердого тіла 16, no. 3 (September 15, 2015): 560–64. http://dx.doi.org/10.15330/pcss.16.3.560-564.

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The comparative investigation of two chemical polishing methods as applied to GaAs substrates is carried out. In both cases the equal etchant Br2+HBr was used. The comparison of etching rates and of surface morphology is carried out. It is revealed that numerous etching pits arise during chemo-dynamical polishing of GaAs (111) В samples but not arise during non-contact chemo-mechanical polishing of the same samples. Besides, last method allows to raise appreciably etching rate as compared with the method of chemo-dynamical polishing. That is, the same etchant behaves as selective or polishing depending on method of polishing. On the basis of worked out model of substrate surface etching near line defect the simulating of etching pit arising is carried out. The results of simulation are consistent with the idea that there are two competing ways of GaAs etching in the etchant Br2+HBr .

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Alias, Ezzah Azimah, Muhammad Esmed Alif Samsudin, Steven DenBaars, James Speck, Shuji Nakamura, and Norzaini Zainal. "N-face GaN substrate roughening for improved performance GaN-on-GaN LED." Microelectronics International 38, no. 3 (August 23, 2021): 93–98. http://dx.doi.org/10.1108/mi-02-2021-0011.

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Purpose This study aims to focus on roughening N-face (backside) GaN substrate prior to GaN-on-GaN light-emitting diode (LED) growth as an attempt to improve the LED performance. Design/methodology/approach The N-face of GaN substrate was roughened by three different etchants; ammonium hydroxide (NH4OH), a mixture of NH4OH and H2O2 (NH4OH: H2O2) and potassium hydroxide (KOH). Hexagonal pyramids were successfully formed on the surface when the substrate was subjected to the etching in all cases. Findings Under 30 min of etching, the highest density of pyramids was obtained by NH4OH: H2O2 etching, which was 5 × 109 cm–2. The density by KOH and NH4OH etchings was 3.6 × 109 and 5 × 108 cm–2, respectively. At standard operation of current density at 20 A/cm2, the optical power and external quantum efficiency of the LED on the roughened GaN substrate by NH4OH: H2O2 were 12.3 mW and 22%, respectively, which are higher than its counterparts. Originality/value This study demonstrated NH4OH: H2O2 is a new etchant for roughening the N-face GaN substrate. The results showed that such etchant increased the density of the pyramids on the N-face GaN substrate, which subsequently resulted in higher optical power and external quantum efficiency to the LED as compared to KOH and NH4OH.

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Misal, Nitin D., and Mudigonda Sadaiah. "Investigation on Surface Roughness of Inconel 718 in Photochemical Machining." Advances in Materials Science and Engineering 2017 (2017): 1–9. http://dx.doi.org/10.1155/2017/3247873.

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The present work is focused on estimating the optimal machining parameters required for photochemical machining (PCM) of an Inconel 718 and effects of these parameters on surface topology. An experimental analysis was carried out to identify optimal values of parameters using ferric chloride (FeCl3) as an etchant. The parameters considered in this analysis are concentration of etchant, etching time, and etchant temperature. The experimental analysis shows that etching performance as well as surface topology improved by appropriate selection of etching process parameters. Temperature of the etchant found to be dominant parameter in the PCM of Inconel 718 for surface roughness. At optimal etching conditions, surface roughness was found to be 0.201 μm.

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Zunic, Zora, Predrag Ujic, Igor Celikovic, and Kenzo Fujimoto. "ECE laboratory in the Vinca institute: Its basic characteristics and fundamentals of electrochemic etching on polycarbonate." Nuclear Technology and Radiation Protection 18, no. 2 (2003): 57–60. http://dx.doi.org/10.2298/ntrp0302057z.

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This paper deals with the introductory aspects of the Electrochemical Etching Laboratory installed at the VINCA Institute in the year 2003. The main purpose of the laboratory is its field application for radon and thoron large-scale survey using passive radon/thoron UFO type detectors. Since the etching techniques together with the laboratory equipment were transferred from the National Institute of Radiological Sciences, Chiba, Japan, it was necessary for both etching conditions to be confirmed and to be checked up^ i. e., bulk etching speeds of chemical etching and electrochemical etching in the VINCA Electrochemical Etching Laboratory itself. Beside this initial step, other concerns were taken into consideration in this preliminary experimental phase such as the following: the measurable energy range of the polycarbonate film, background etch pit density of the film and its standard deviation and reproducibility of the response to alpha particles for different sets of etchings.

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Tellier, C. R., T. G. Leblois, and A. Charbonnieras. "Chemical Etching of {hk0} Silicon Plates in EDP Part I: Experiments and Comparison with TMAH." Active and Passive Electronic Components 23, no. 1 (2000): 37–51. http://dx.doi.org/10.1155/apec.23.37.

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This paper deals with the anisotropic chemical etching of various silicon plates etched in EDP. Changes with orientation in geometrical features of etched surface and in the etching shape of starting circular sections are systematically investigated. These etching shapes are compared with shapes produced by etching in KOH and TMAH solutions; This experimental study allows us to determine the dissolution slowness surface for the EDP solution and to investigate the real influence of the etchant on two dimensional and three dimensional etching shapes.

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Park, Tae Gun, Jong Won Han, and Sang Woo Lim. "Selective Si3N4 Etching for 3D NAND Integration by Using Low Concentration of H3PO4." Solid State Phenomena 346 (August 14, 2023): 137–42. http://dx.doi.org/10.4028/p-0pjfvo.

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This study investigated the etching kinetics of Si3N4 in various concentration of H3PO4 solution and the effect of Si3N4 etching enhancers on the etching process, particularly for 3D NAND trench structures. 30 wt% H3PO4 was used to etch Si3N4, which can produce higher Si3N4/SiO2 etching selectivity and similar Si3N4 etching rate compared to a conventional 85 wt% H3PO4. 30 wt% H3PO4 showed significantly improved etching performance for the Si3N4/SiO2 3D NAND structure as compared to 85 wt% H3PO4. In particular, the transportation ability of H3PO4 into 3D NAND trench structures can be improved by reducing viscosity of etchant, which can be obtained by reducing the concentration of H3PO4. In addition, Si3N4 etching enhancers were introduced to accelerate the Si3N4 etching kinetics in 30 wt% H3PO4. Addition of such additives improved the Si3N4 etching rate and Si3N4/SiO2 etching selectivity while suppressing oxide regrowth. The results provide valuable insights for optimizing selective Si3N4 etching process in 3D NAND structures.

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11

Wang, Qi, Kehong Zhou, Shuai Zhao, Wen Yang, Hongsheng Zhang, Wensheng Yan, Yi Huang, and Guodong Yuan. "Metal-Assisted Chemical Etching for Anisotropic Deep Trenching of GaN Array." Nanomaterials 11, no. 12 (November 24, 2021): 3179. http://dx.doi.org/10.3390/nano11123179.

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Realizing the anisotropic deep trenching of GaN without surface damage is essential for the fabrication of GaN-based devices. However, traditional dry etching technologies introduce irreversible damage to GaN and degrade the performance of the device. In this paper, we demonstrate a damage-free, rapid metal-assisted chemical etching (MacEtch) method and perform an anisotropic, deep trenching of a GaN array. Regular GaN microarrays are fabricated based on the proposed method, in which CuSO4 and HF are adopted as etchants while ultraviolet light and Ni/Ag mask are applied to catalyze the etching process of GaN, reaching an etching rate of 100 nm/min. We comprehensively explore the etching mechanism by adopting three different patterns, comparing a Ni/Ag mask with a SiN mask, and adjusting the etchant proportion. Under the catalytic role of Ni/Ag, the GaN etching rate nearby the metal mask is much faster than that of other parts, which contributes to the formation of deep trenches. Furthermore, an optimized etchant is studied to restrain the disorder accumulation of excessive Cu particles and guarantee a continuous etching result. Notably, our work presents a novel low-cost MacEtch method to achieve GaN deep etching at room temperature, which may promote the evolution of GaN-based device fabrication.

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Liu, Zhuang, Lin Zhu, Jing Lin, and Zhi Hui Sun. "Study of Super Hydrophobic Films on Pre-Sensitized Plate Aluminium Substrate." Applied Mechanics and Materials 200 (October 2012): 427–29. http://dx.doi.org/10.4028/www.scientific.net/amm.200.427.

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A simple chemical etching method was developed for corrosion of the pre-sensitized plate aluminium substrate in order to be a rough surface. After the chemical etched surface was treated with fluorination, the pre-sensitized (PS) plate aluminium (Al) substrate surface exhibits a super-hydrophobic property. The effects of the etching time and the etchant concentration on the super-hydrophobici were investigated, and the results show the contact angle of hydrofluoric firstly increases then reduce with acid etching time increasing, and the optimum etching time is 12 min; the contact angle of hydrofluoric firstly increases then reduce with acid etchant concentration increasing, and the optimum etchant concentration is 3 mol /L. When the contact angle increases, the droplet and solid surface tension increases. Film base fine structure of the rough surface is the key to the formation of hydrophobic.

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Ambrož, O., J. Čermák, P. Jozefovič, and Š. Mikmeková. "Automated color etching of aluminum alloys." Practical Metallography 59, no. 8-9 (August 1, 2022): 459–74. http://dx.doi.org/10.1515/pm-2022-1014.

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Abstract Color metallography of aluminum alloys can provide new structural knowledge or extend and refine structural knowledge compared to a black and white image. The basic principle of color metallography is to create a suitable film by etching. On samples coated with a suitable film, light interference is caused by the splitting of the incident light into components reflected at the air-layer interface and the layer-metal interface. The thickness of the film essentially determines at which colors the interference occurs. For films of suitable thickness, interference occurs in the blue, green and yellow regions. The film thickness depends on the chemical composition of the sample material, the chemical composition of the etchant and the etching time. If the etching conditions are kept constant (etchant type, etching time) and the chemical composition of the individual micro-areas changes significantly, it will be possible to distinguish the microareas by color contrast in the bright field. The results of color etching of aluminum alloys in different types of etchants will be presented. Using an automated apparatus, the same etching conditions will be maintained, including time and repeatability of movements in the etching, cleaning and drying process.

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Ambrož, O., J. Čermák, P. Jozefovič, and Š. Mikmeková. "Effects of etchant stirring on the surface quality of the metallography sample." Journal of Physics: Conference Series 2572, no. 1 (August 1, 2023): 012011. http://dx.doi.org/10.1088/1742-6596/2572/1/012011.

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Abstract Despite its predominantly empirical nature, metallographic etching remains an important sample preparation method that enables microstructural characterization. The poor repeatability is due to the ignorance of etching mechanisms and the human factor, which is mainly associated with the conventional approach. This approach is most commonly practiced by manual immersion of the sample in the etchant. The solution should be gently stirred so that reaction products do not settle on the surface and uneven etching does not occur. Often, stirring is provided by the sample itself or by a magnetic bar. In terms of spatial orientation, etching with the polished surface facing upwards allows the surface to be observed during the process. Some authors recommend etching with the polished surface downwards to minimize the deposition of reaction products. In some cases, a vertical orientation of the sample is recommended to reduce pitting. In this paper, the effect of the etchant stirring method on the surface quality of a metallographic structural steel specimen will be presented. In addition to different etchant stirring methods, different spatial orientations of the sample will also be investigated. To ensure better repeatability and accurate etching time, the samples will be etched using our automated apparatus. The resulting surface of the samples will be analysed using light optical microscopy (LOM) and confocal laser scanning microscopy (CLSM). The development of more reproducible etching methods is essential to obtain accurate microstructure information without artifacts and for advanced quantitative image analysis using deep learning.

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Kim, Dong Hyeon, Chanwoo Lee, Byeong Geun Jeong, Sung Hyuk Kim, and Mun Seok Jeong. "Fabrication of highly uniform nanoprobe via the automated process for tip-enhanced Raman spectroscopy." Nanophotonics 9, no. 9 (June 17, 2020): 2989–96. http://dx.doi.org/10.1515/nanoph-2020-0210.

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AbstractIn a tip-enhanced Raman spectroscopy (TERS) system, using a sharp nanotip that comprises a noble metal is critical to attaining high spatial resolution and highly enhanced Raman scattering. A strongly acidic solution is typically used to fabricate gold nanotips in a quick and reliable manner. However, using an acidic solution could corrode the etching system, thereby posing hazardous problems. Therefore, both the corrosion of the etching system and human error induced by the conventional method considerably decrease the quality and reproducibility of the tip. In this study, we significantly increased the reproducibility of tip fabrication by automating the electrochemical etching system. In addition, we optimized the etching conditions for an etchant that comprised a KCl solution to which ethanol was added to overcome the limitations of the acidic etchant. The automated etching system significantly increases the yield rate of tip-fabrication reproducibility from 65 to 95%. The standard deviation of the radius of curvature decreased to 7.3 nm with an average radius of curvature of 30 nm. Accordingly, the automated electrochemical etching system might improve the efficiency of TERS.

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Ting, Huey Tze, Khaled A. Abou-El-Hossein, and Han Bing Chua. "Etch Rate and Dimensional Accuracy of Machinable Glass Ceramics in Chemical Etching." Advances in Science and Technology 65 (October 2010): 251–56. http://dx.doi.org/10.4028/www.scientific.net/ast.65.251.

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Machinable glass ceramic (MGC) is well known in the micro-electromechanical system and semiconductor industry. Chemical etching is used in this experiment to study the performance of MGC. The etching rate of MGC and its accuracy by indentation method is studied. The categoric parameter applied here is the type of chemical etchant used: hydrochloric (HCl), hydrophosphoric (H3PO4) and hydrobromic (HBr) acids; and, numerical parameters are etching temperature and etching solution. The experimental investigation that was carried out is governed by design of experiment (DoE).

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Schnarr, H. "Less is sometimes more – some examples of the reduction of hazardous substances in metallographic etching." Practical Metallography 61, no. 7 (July 1, 2024): 420–46. http://dx.doi.org/10.1515/pm-2024-0038.

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Abstract In metallography, the choice of the right etchant is crucial for visualizing the microstructure. As conventional etching agents generally contain a more or less high proportion of hazardous substances that need to be reduced in the future, examples are given of how this reduction is possible in principle. This reduction in hazardous substances is mainly achieved through microscopy contrasts, dilution of etching solutions and electrolytic etching.

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Hao, Yuhua, and Xia Wang. "Effects of the Photoelectrochemical Etching in Hydrogen Fluride (HF) on the Optoelectrical Properties of Ga₂O₃." Journal of Physics: Conference Series 2112, no. 1 (November 1, 2021): 012006. http://dx.doi.org/10.1088/1742-6596/2112/1/012006.

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Abstract Photoelectrochemical (PEC) etching is preferred to produce micro-and nano-structures for constructing Ga2O3-based electronics and optoelectronics, owing to its numerous controllable parameters. During the devices fabrications, beyond the wet chemical and dry (plasma) etching produces, PEC etching also leads to device degradations inordinately. In this work, the Ga2O3 thin film was PEC etched by hydrogen fluride (HF) etchant, and its opto-electric deep-ultraviolet sensing performances, including photo-to-dark current ratio, responsivity, and response speed, before and after PEC etching were analyzed and discussed.

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Yusoh, Siti Noorhaniah, and Khatijah Aisha Yaacob. "Effect of tetramethylammonium hydroxide/isopropyl alcohol wet etching on geometry and surface roughness of silicon nanowires fabricated by AFM lithography." Beilstein Journal of Nanotechnology 7 (October 17, 2016): 1461–70. http://dx.doi.org/10.3762/bjnano.7.138.

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The optimization of etchant parameters in wet etching plays an important role in the fabrication of semiconductor devices. Wet etching of tetramethylammonium hydroxide (TMAH)/isopropyl alcohol (IPA) on silicon nanowires fabricated by AFM lithography is studied herein. TMAH (25 wt %) with different IPA concentrations (0, 10, 20, and 30 vol %) and etching time durations (30, 40, and 50 s) were investigated. The relationships between etching depth and width, and etching rate and surface roughness of silicon nanowires were characterized in detail using atomic force microscopy (AFM). The obtained results indicate that increased IPA concentration in TMAH produced greater width of the silicon nanowires with a smooth surface. It was also observed that the use of a longer etching time causes more unmasked silicon layers to be removed. Importantly, throughout this study, wet etching with optimized parameters can be applied in the design of the devices with excellent performance for many applications.

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Yao, Yong Zhao, Yukari Ishikawa, Yoshihiro Sugawara, Hiroaki Saitoh, Katsunori Danno, Hiroshi Suzuki, Yoichiro Kawai, and Noriyoshi Shibata. "Dislocation Revelation in Highly Doped N-Type 4H-SiC by Molten KOH Etching with Na₂O₂ Additive." Materials Science Forum 679-680 (March 2011): 290–93. http://dx.doi.org/10.4028/www.scientific.net/msf.679-680.290.

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We have proposed a new wet etching recipe using molten KOH and Na2O2 as the etchant (“KN etching”) for dislocation revelation in highly doped n-type 4H-SiC (n+-4H-SiC). Threading screw dislocations (TSDs) and threading edge dislocations (TEDs) have been clearly revealed as hexagonal etch pits differing in pit sizes, and basal plane dislocations (BPDs) as seashell-shaped pits. This new etching recipe has provided a solution to the problem that conventional KOH etching is not effective for dislocation identification in 4H-SiC if the electron concentration is high (>mid-1018 cm-3). We have investigated the effect of SiC off-cut angle on KN etching and it has been shown that the “KN etching” is applicable for the n+-SiC substrate with off-angle from 0o to 8o.

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Son, Chang Jin, Taeh Yeon Kim, Tae Gun Park, and Sang Woo Lim. "Is Highly Selective Si₃N₄/SiO₂ Etching Feasible without Phosphoric Acid?" Solid State Phenomena 282 (August 2018): 147–51. http://dx.doi.org/10.4028/www.scientific.net/ssp.282.147.

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Si3N4 film could be selectively removed by a special H3PO4-free etchant. In order to increase Si3N4 etching rate and Si3N4/SiO2 etch selectivity, various additives were added to H3PO4-free etchant. The optimization of additives into H3PO4-free solution, a comparable Si3N4 etching rate with 50 times increased Si3N4/SiO2 etch selectivity was obtained as compared to the conventional H3PO4 process.

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Ueda, Dai, Yousuke Hanawa, Hiroaki Kitagawa, Naozumi Fujiwara, Masayuki Otsuji, Hiroaki Takahashi, and Kazuhiro Fukami. "Effect of Hydrophobicity and Surface Potential of Silicon on SiO₂ Etching in Nanometer-Sized Narrow Spaces." Solid State Phenomena 314 (February 2021): 155–60. http://dx.doi.org/10.4028/www.scientific.net/ssp.314.155.

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Wet etching in nanometer-sized three-dimensional spaces creates new challengesbecause of the scaling of semiconductor devices with complex 3D architecture. Wet etching withinspaces is affected by the mass transport of the etchant ions that are impacted by the hydrophobicityand surface potential of surface. However, the kinetics of chemical reactions within the spaces is stillunclear.In this paper, we studied the effect of hydrophobicity and surface potential of silicon surface on SiO2etching in nanometer-sized narrow spaces by adding various additive components to etching solutions.We found that the transport of etchant ions into narrow spaces is governed by controlling thehydrophobicity and surface potential of the confined system walls.

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Fang, Jinyang, Qingke Zhang, Xinli Zhang, Feng Liu, Chaofeng Li, Lijing Yang, Cheng Xu, and Zhenlun Song. "Influence of Etchants on Etched Surfaces of High-Strength and High-Conductivity Cu Alloy of Different Processing States." Materials 17, no. 9 (April 24, 2024): 1966. http://dx.doi.org/10.3390/ma17091966.

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With the continuous integration of semiconductor devices, the requirements of the size accuracy and surface quality of etched lead frames are stricter. The etchant is a key factor in the etching process and etched surface quality, while the effects of the difference in etchants on the etched surface morphology of Cu alloy have not been directly studied. In this study, aqua regia, acidic FeCl3 and two CuCl2 solutions were used as etchants, and different CuCrSn specimens were etched and characterized. The results show that the etching rate in aqua regia is high, and the grain orientation, grain boundary (GB) and dislocations have significant influences on the local etching rate. The preferential etching of some atomic planes forms steps between the grains with different orientations, and preferential etching around the GB and dislocation group forms grooves, resulting in high surface roughness. For the surfaces etched by the FeCl3 and CuCl2 etchants, the steps and grooves are blurred; thus, they are less rough. The CuCrSn alloy surface etched by the aqua regia is clean, with little Cr-rich particles, while high-density Cr-rich particles remain on the surfaces etched by the FeCl3 and CuCl2 etchants. For the same kind of etchant, the ion concentration can affect the etching mechanism, rate and the etched surface morphology.

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Amirabadi, Hossein, and M. Rakhshkhorshid. "An Analytical Model for Chemical Etching in One Dimensional Space." Advanced Materials Research 445 (January 2012): 167–70. http://dx.doi.org/10.4028/www.scientific.net/amr.445.167.

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In this paper an analytical model for chemical etching in one dimensional space has been presented. Regarding to the special specifications of Ferric chloride, etching of an Aluminum work piece exposed to Ferric chloride etchant has been modeled. The proposed model shows that, in the condition of constant reaction parameters, etching rate is a linear function of time. Excellent agreement between the proposed model and the experimental results, published by Çakır (2008), validates the model. By generalization the proposed model, etching rate, or in the other word depth of etch in a specified time, for different materials with different etchants can be predicted.

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Li, Liyi, Colin M. Holmes, Jinho Hah, Owen J. Hildreth, and Ching P. Wong. "Uniform Metal-assisted Chemical Etching and the Stability of Catalysts." MRS Proceedings 1801 (2015): 1–8. http://dx.doi.org/10.1557/opl.2015.574.

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ABSTRACTRecently, metal-assisted chemical etching (MaCE) has been demonstrated as a promising technology in fabrication of uniform high-aspect-ratio (HAR) micro- and nanostructures on silicon substrates. In this work, MaCE experiments on 2 μm-wide line patterns were conducted using Au or Ag as catalysts. The performance of the two catalysts show sharp contrast. In MaCE with Au, a HAR trench was formed with uniform geometry and vertical sidewall. In MaCE with Ag, shallow and tapered etching profiles were observed, which resembled the results from isotropic etching. The sidewall tapering phenomena can be explained by the dissolution and re-deposition of the Ag catalyst in the etchant solution. The existence of Ag that was redeposited on the sidewall was further confirmed by energy dispersive spectrum. Also, etchant composition is found to play a profound role in influencing the etching profile by the Ag catalysts.

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Rahim, Rosminazuin A., Badariah Bais, and Majlis Burhanuddin Yeop. "Simple Microcantilever Release Process of Silicon Piezoresistive Microcantilever Sensor Using Wet Etching." Applied Mechanics and Materials 660 (October 2014): 894–98. http://dx.doi.org/10.4028/www.scientific.net/amm.660.894.

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In this paper, a simple microcantilever release process using anisotropic wet etching is presented. The microcantilever release is conducted at the final stage of the fabrication of piezoresistive microcantilever sensor. Issues related to microcantilever release such as microscopic roughness and macroscopic roughness has been resolved using simple technique. By utilizing silicon oxide (SiO2) as the etch stop for the wet etching process, issues related to microscopic roughness can be eliminated. On the other hand, proper etching procedure with constant stirring of the etchant solution of KOH anisotropic etching significantly reduces the notching effect contributed by the macroscopic roughness. Upon the completion of microcantilever release, suspended microcantilever of 2μm thick is realized with the removal of SiO2layer using Buffered Oxide Etching (BOE).

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Tu, Wei-Hsiang, Wen-Chang Chu, Chih-Kung Lee, Pei-Zen Chang, and Yuh-Chung Hu. "Effects of etching holes on complementary metal oxide semiconductor–microelectromechanical systems capacitive structure." Journal of Intelligent Material Systems and Structures 24, no. 3 (June 11, 2012): 310–17. http://dx.doi.org/10.1177/1045389x12449917.

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Etching the large area of sacrificial layer under the microstructure to be released is a common method used in microelectromechanical systems technology. In order to completely release the microstructures, many etching holes are often required on the microstructure to enable the etchant to completely etch the sacrificial layer. However, the etching holes often alter the electromechanical properties of the micro devices, especially capacitive devices, because the fringe fields induced by the etching holes can significantly alter the electrical properties. This article is aimed at evaluating the fringe field capacitance caused by etching holes on microstructures. The authors aim to find a general capacitance compensation formula for the fringe capacitance of etching holes by the use of ANSYS simulation. According to the simulation results, the design of a capacitive structure with small etching holes is recommended to prevent an extreme capacitance decrease. In conclusion, this article provides a fringing field capacitance estimation method that shows the capacitance compensation tendency of the design of etching holes; this method is expected to be applicable to the design in capacitive devices of complementary metal oxide semiconductor–microelectromechanical systems technology.

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Kikkawa, Yuki, Yuzan Suzuki, Kohei Saito, Hiroto Yarimizu, Satoko Kanamori, Tomoaki Sato, and Toru Nagashima. "Alkali Wet Chemicals for Ru with Advanced Semiconductor Technology Nodes." Solid State Phenomena 346 (August 14, 2023): 325–30. http://dx.doi.org/10.4028/p-08chsp.

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Wet chemicals for ruthenium (Ru) etching are required for the formation of reliable Ru interconnects in advanced semiconductor technology nodes. In the present study, a novel alkali wet etchant, referred to as TK-1, has been developed in order to overcome issues with conventional Ru etchants, such as a low etch rate and the formation of toxic RuO4 gas. Regardless of the Ru deposition process, TK-1 exhibits a high Ru etching selectivity of greater than 100 relative to dielectric and liner materials. It also suppresses the production of RuO4 during the etching process. TK-1 has potential applications for Ru recess etching during fully self-aligned via fabrication.

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Wu, Bing-Rui, Sin-Liang Ou, Shih-Yung Lo, Hsin-Yuan Mao, Jhen-Yu Yang, and Dong-Sing Wuu. "Texture-Etched SnO2Glasses Applied to Silicon Thin-Film Solar Cells." Journal of Nanomaterials 2014 (2014): 1–9. http://dx.doi.org/10.1155/2014/907610.

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Transparent electrodes of tin dioxide (SnO2) on glasses were further wet-etched in the diluted HCl:Cr solution to obtain larger surface roughness and better light-scattering characteristic for thin-film solar cell applications. The process parameters in terms of HCl/Cr mixture ratio, etching temperature, and etching time have been investigated. After etching process, the surface roughness, transmission haze, and sheet resistance of SnO2glasses were measured. It was found that the etching rate was increased with the additions in etchant concentration of Cr and etching temperature. The optimum texture-etching parameters were 0.15 wt.% Cr in 49% HCl, temperature of 90°C, and time of 30 sec. Moreover, silicon thin-film solar cells with the p-i-n structure were fabricated on the textured SnO2glasses using hot-wire chemical vapor deposition. By optimizing the texture-etching process, the cell efficiency was increased from 4.04% to 4.39%, resulting from the increment of short-circuit current density from 14.14 to 15.58 mA/cm2. This improvement in cell performances can be ascribed to the light-scattering effect induced by surface texturization of SnO2.

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Lamichhane, Shobha Kanta. "Experimental investigation on anisotropic surface properties of crystalline silicon." BIBECHANA 8 (January 15, 2012): 59–66. http://dx.doi.org/10.3126/bibechana.v8i0.4828.

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Anisotropic etching of silicon has been studied by wet potassium hydroxide (KOH) etchant with its variation of temperature and concentration. Results presented here are temperature dependent etch rate along the crystallographic orientations. The etching rate of the (111) surface family is of prime importance for microfabrication. However, the experimental values of the corresponding etch rate are often scattered and the etching mechanism of (111) remains unclear. Etching and activation energy are found to be consistently favorable with the thermal agitation for a given crystal plane. Study demonstrate that the contribution of microscopic activation energy that effectively controls the etching process. Such a strong anisotropy in KOH allows us a precious control of lateral dimensions of the silicon microstructure.Keywords: microfabrication; activation energy; concentration; anisotropy; crystal planeDOI: http://dx.doi.org/10.3126/bibechana.v8i0.4828 BIBECHANA 8 (2012) 59-66

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Ding, Jingxiu, Ruipeng Zhang, Yuchun Li, David Wei Zhang, and Hongliang Lu. "Investigation of a Macromolecular Additive on the Decrease of the Aluminum Horizontal Etching Rate in the Wet Etching Process." Metals 12, no. 5 (May 8, 2022): 813. http://dx.doi.org/10.3390/met12050813.

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The effect of a macromolecular additive on the etching rate of aluminum (Al) horizontal etching in the wet process was investigated in this work. The horizontal etching in the Al wet etching process became more evident as the film Al becomes thicker. The proposed macromolecule additive, including polyethylene-polypropylene glycol, was added into the Al etchant solution to reduce the Al horizontal etching rate (ER). The undercut problem during metal patterning can then be improved. By using this method, the Al horizontal ER was reduced from 2.0 to 0.9 μm per minute and the selection ratio between the horizontal and vertical ER was effectively improved from 3 to 1.3 times. As well, a hypothesis of physical mechanism for the improvement was proposed. The dispersed particles from the additive emulsion inhibited the transport and exchange of liquid in a horizontal direction. This work provides an alternative reference to improve the selection ratio performance in the metal wet etching process compared with that when using traditional method.

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Гармаш, В. И., В. Е. Земляков, В. И. Егоркин, А. В. Ковальчук, and С. Ю. Шаповал. "Исследование влияния атомарного состава на скорость плазмохимического травления нитрида кремния в силовых транзисторах на основе AlGaN/GaN-гетероперехода." Физика и техника полупроводников 54, no. 8 (2020): 748. http://dx.doi.org/10.21883/ftp.2020.08.49646.9398.

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The effect of atomic composition on the rate of plasma chemical etching of silicon nitride in power transistors based on an AlGaN / GaN heterojunction is studied. It is shown how the subsequent process of its plasma-chemical etching depends on the configuration of the incorporation of hydrogen impurity atoms into the molecular structure of the silicon nitride deposited in the plasma. The dependence of the etching rate on the parameters of the process (the working pressure in the chamber, the power of the plasma generator, the flow of working gases, the deposition temperature) is investigated. It was shown that the etching rate of the HxSirNzHy film does not depend directly on the hydrogen content, but significantly depends on the ratio of [Si-H] / [N-H] bonds. The etching rate of HxSirNzHy in a high-density plasma at low powers is much less dependent on the configuration of hydrogen bonds than the etching rate of this dielectric in a buffer etchant.

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Rath, P., J. C. Chai, Y. C. Lam, V. M. Murukeshan, and H. Zheng. "A Total Concentration Fixed-Grid Method for Two-Dimensional Wet Chemical Etching." Journal of Heat Transfer 129, no. 4 (October 21, 2006): 509–16. http://dx.doi.org/10.1115/1.2709654.

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A total concentration fixed-grid method is presented in this paper to model the two-dimensional wet chemical etching. Two limiting cases are discussed, namely—the diffusion-controlled etching and the reaction-controlled etching. A total concentration, which is the sum of the unreacted and the reacted etchant concentrations, is defined. Using this newly defined total concentration, the governing equation also contains the interface condition. A new update procedure for the reacted concentration is formulated. For demonstration, the finite-volume method is used to solve the governing equation with prescribed initial and boundary conditions. The effects of reaction rate at the etchant–substrate interface are examined. The results obtained using the total concentration method, are compared with available results from the literature.

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Shimozono, Naoki, Mikinori Nagano, Takaaki Tabata, and Kazuya Yamamura. "Study on In Situ Etching Rate Monitoring in Numerically Controlled Local Wet Etching." Key Engineering Materials 523-524 (November 2012): 34–39. http://dx.doi.org/10.4028/www.scientific.net/kem.523-524.34.

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Numerically controlled local wet etching (NC-LWE) is very promising technique for deterministic figuring of ultraprecision optical devices, such as aspherical lens, photo mask substrate and X-ray or neutron focusing mirror. NC-LWE technique is non-contact removal process using chemical reaction between etchant and surface of workpiece, so this technique enables us to figure the objective shape without introduction both substrate deformation and sub-surface damage. It is essential to measure temperature and concentration of the etchant to maintain the material removal rate constant over a processing time, since the etching rate of NC-LWE strongly depends on these parameters. Hydrofluoric (HF) acid solution is used as an etchant for synthesized quartz glass. We aim to develop an in situ monitoring system of etchant concentration using Raman spectroscopy and electric conductivity measurement. Raman spectroscopy measurement result indicates that there is a good linear relationship between HF concentration and intensity ratio of two specific Raman bands.

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Wu, Ping, Xue Ping Xu, Ilya Zwieback, and John Hostetler. "Study of Etching Processes for SiC Defect Analysis." Materials Science Forum 897 (May 2017): 363–66. http://dx.doi.org/10.4028/www.scientific.net/msf.897.363.

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We investigated selective etching of SiC in molten KOH + NaOH + Na2O2 mixtures in application to defect analysis. Etch rate was measured as a function of etchant composition, temperature and other process variables. Optimal etching conditions were established for reliable differentiation between TSDs, TEDs, BPDs and stacking faults (SF).

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Wilson, Sara M., Wen Lien, David P. Lee, and William J. Dunn. "Confocal microscope analysis of depth of etch between self-limiting and traditional etchant systems." Angle Orthodontist 87, no. 5 (May 10, 2017): 766–73. http://dx.doi.org/10.2319/120816-880.1.

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ABSTRACT Objective: To see whether there is an advantage to using a self-limiting phosphoric acid etchant versus a traditional 34% phosphoric acid etchant for bonding by measuring the depth of etch at multiple time intervals. Materials and Methods: A total of 25 bovine teeth were mounted and etched on the facial surface with two different etchants: standard 34% phosphoric acid and a self-limiting 35% phosphoric acid etchant at varied time intervals of 15, 30, 60, 90, and 120 seconds. Teeth were scanned using a three-dimensional laser confocal scanning microscope prior to etching and scanned again after etching to determine the depth of enamel etched compared to the baseline enamel surface prior to etching. Results: The 34% phosphoric acid etchant etched significantly deeper than the self-limiting etch. Etch times exceeding 30 seconds also etched significantly deeper for both types of etchant. Conclusion: The etch depth of the self-limiting etchant was consistently less than the standard etchant. Both types of etchant etched deeper after 30 seconds, but the depth of etch at 120 seconds was not different than at 60 seconds, indicating that both etchants are somewhat self-limiting in depth. Therefore, there is no advantage to using the self-limiting etchant.

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Kumar Katta, Prashanth. "Etching in Dentistry." Indian Journal of Dental Education 13, no. 1 (2020): 17–20. http://dx.doi.org/10.21088/ijde.0974.6099.13120.2.

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Kim, Jonghyeok, Byungjoo Kim, Jiyeon Choi, and Sanghoon Ahn. "The Effects of Etchant on via Hole Taper Angle and Selectivity in Selective Laser Etching." Micromachines 15, no. 3 (February 25, 2024): 320. http://dx.doi.org/10.3390/mi15030320.

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This research focuses on the manufacturing of a glass interposer that has gone through glass via (TGV) connection holes. Glass has unique properties that make it suitable for 3D integrated circuit (IC) interposers, which include low permittivity, high transparency, and adjustable thermal expansion coefficient. To date, various studies have suggested numerous techniques to generate holes in glass. In this study, we adopt the selective laser etching (SLE) technique. SLE consists of two processes: local modification via an ultrashort pulsed laser and chemical etching. In our previous study, we found that the process speed can be enhanced by changing the local modification method. For further enhancement in the process speed, in this study, we focus on the chemical etching process. In particular, we try to find a proper etchant for TGV formation. Here, four different etchants (HF, KOH, NaOH, and NH4F) are compared in order to improve the etching speed. For a quantitative comparison, we adopt the concept of selectivity. The results show that NH4F has the highest selectivity; therefore, we can tentatively claim that it is a promising candidate etchant for generating TGV. In addition, we also observe a taper angle variation according to the etchant used. The results show that the taper angle of the hole is dependent on the concentration of the etchant as well as the etchant itself. These results may be applicable to various industrial fields that aim to adjust the taper angle of holes.

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Yao, Yong Zhao, Yukari Ishikawa, Yoshihiro Sugawara, and Koji Sato. "Removal of Mechanical-Polishing-Induced Surface Damages on 4H-SiC Wafers by Using Chemical Etching with Molten KCl+KOH." Materials Science Forum 778-780 (February 2014): 746–49. http://dx.doi.org/10.4028/www.scientific.net/msf.778-780.746.

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High temperature (>1000 °C) chemical etching using molten KCl or molten KCl+KOH as the etchant has been carried out to remove the mechanical-polishing (MP) induced damage layer from 4H-SiC surface. Atomic force microscopy observations have shown that line-shaped surface scratches that have appeared on the as-MPed surface could be completely removed by KCl-only etching or by KCl+KOH etching (KCl:KOH=99:1 in weight) at ~1100 °C. Between the two recipes, KCl+KOH etching has shown a higher etch rate (6~7 times) and is able to remove ~9 μm and ~36 μm-thick damage layer from the Si (0001) and the C(000-1) surface, respectively. Besides, KCl+KOH etching seems to have formed a Si (0001) surface covered with atomic steps while KCl-only etched surface is featured with nanometer-scale pores.

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Liu, Dan, Guoliang Chen, Zhonghao Huang, Jianguo An, Dongwon Jung, Wenxiang Chen, Xu Wu, et al. "P‐7.11: Effect of etching conditions, MoNb thickness on gate profile and CD Bias of ADS Pro TFT." SID Symposium Digest of Technical Papers 55, S1 (April 2024): 1083–86. http://dx.doi.org/10.1002/sdtp.17284.

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The etched MoNb/Cu stack film is widely used as gate electrodes for ADS Pro TFTs. The CD Bias and profile angle(PA) are two important performance parameters for wet etching. The product‐specific bottom MoNb thickness and the fluctuation of wet etching conditions(time, temperature, and Cu ion concentration) make it difficult to precisely control the etching quality, thus it is of great significance to identify the influence of the above two factors on CD Bias and PAs. In this paper, the wet etching time, temperature and Cu ion concentration are taken as independent variables, and 11 different etching conditions are arranged based on the uniform experiments design to etch MoNb/Cu samples with two different MoNb thicknesses. The experiments reseluts shows that for the etched two MoNb/Cu stacks (15/300 nm, 30/300 nm) samples, the CD Bias and PAs are in the range of 0.22~0.73 µm and 40~51°, respectively. Both the CD Bias and PAs increase with the bottom MoNb thickness, etching temperature, etching time or Cu concentration, and the PAs increases with CD Bias. The etchant may form a reflux path during the etching process, along which the etching rate decreases. The difference between the etching rates at the top and bottom of the electrode contributes to the increase of PAs and CD Bias with etching severity. In the MoNb/Cu sidewall, MoNb acts as an anode due to the low corrosion potential, and the galvanic effect leads to the acceleration of MoNb etching, which ultimately results in the increase of PA and CD Bias under the thick MoNb.

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Philipsen, Harold, Sander Teck, Nils Mouwen, Wouter Monnens, and Quoc Toan Le. "Wet-Chemical Etching of Ruthenium in Acidic Ce⁴⁺ Solution." Solid State Phenomena 282 (August 2018): 284–87. http://dx.doi.org/10.4028/www.scientific.net/ssp.282.284.

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The wet-chemical etching of ruthenium in acidic solutions of cerium (IV) has been investigated using electrochemical methods. Etch rates were determined using Rutherford backscattering spectroscopy (RBS) and post-etching surface roughness was investigated using atomic force microscopy (AFM). Low-k material is compatible with the etchant, however, residues were formed.

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Cansizoglu, Mehmet F., Mesut Yurukcu, and Tansel Karabacak. "Ripple Formation during Oblique Angle Etching." Coatings 9, no. 4 (April 22, 2019): 272. http://dx.doi.org/10.3390/coatings9040272.

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Chemical removal of materials from the surface is a fundamental step in micro- and nano-fabrication processes. In conventional plasma etching, etchant molecules are non-directional and perform a uniform etching over the surface. However, using a highly directional obliquely incident beam of etching agent, it can be possible to engineer surfaces in the micro- or nano- scales. Surfaces can be patterned with periodic morphologies like ripples and mounds by controlling parameters including the incidence angle with the surface and sticking coefficient of etching particles. In this study, the dynamic evolution of a rippled morphology has been investigated during oblique angle etching (OAE) using Monte Carlo simulations. Fourier space and roughness analysis were performed on the resulting simulated surfaces. The ripple formation was observed to originate from re-emission and shadowing effects during OAE. Our results show that the ripple wavelength and root-mean-square roughness evolved at a more stable rate with accompanying quasi-periodic ripple formation at higher etching angles (θ > 60°) and at sticking coefficient values (Sc) 0.5 ≤ Sc ≤ 1. On the other hand, smaller etching angle (θ < 60°) and lower sticking coefficient values lead to a rapid formation of wider and deeper ripples. This result of this study can be helpful to develop new surface patterning techniques by etching.

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Deprédurand, Valérie, Tobias Bertram, Maxime Thévenin, Nathalie Valle, Jean-Nicolas Audinot, and Susanne Siebentritt. "Alternative Etching for Improved Cu-rich CuInSe2 Solar Cells." MRS Proceedings 1771 (2015): 163–68. http://dx.doi.org/10.1557/opl.2015.447.

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ABSTRACTTwo alternative chemical etchings (aqueous solution of bromine and bromine methanol solution) have been here tested to replace the KCN etching step in Cu-rich CuInSe2 based solar cells fabrication process. This new oxidative etch aims also at smoothing and thinning the as-grown films. This directly affects the interface between the absorber and the CdS buffer, interface which causes problems for Cu-rich solar cells. We present here the effect of these two alternative etchings on both the absorber surface and the solar cells parameters: whereas the bromine methanol etching destroys the solar cell, the aqueous solution of bromine leads to an improvement of the device through reduced interface and tunneling enhanced recombination.

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Choi, Woong, Sanghyun Moon, and Jihyun Kim. "Photo-Enhanced Inverse Metal-Assisted Chemical Etching of α-Ga₂O₃grown on Al₂O₃." ECS Meeting Abstracts MA2023-01, no. 32 (August 28, 2023): 1833. http://dx.doi.org/10.1149/ma2023-01321833mtgabs.

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Si-based semiconductor devices are not suitable for stable operations in the aerospace environments. Among the ultra-wide bandgap semiconductor materials, gallium oxide (Ga2O3) is attracting attention as the next-generation material for high-power semiconductor devices in extreme condition beyond Si, owing to its large band gap of 4.5-5.3 eV, high breakdown electric fields of 7-10 MV/cm, excellent chemical and thermal stability and radiation hardness. Alpha gallium oxide (α-Ga2O3) has the largest bandgap (4.8-5.3 eV) and the highest breakdown electric fields (~10 MV/cm) among the five Ga2O3 polymorphs, which facilitates the application of α-Ga2O3 as a high power device. However, the research on etching technology for α-Ga2O3 is rare. Etching technology is a crucial step of device fabrication. Chemical etching is free from plasma-induced damage which leads to superior device performance compared with dry etching, and high throughput with low cost is beneficial to industrial implementations. Chemical stability of Ga2O3 hinders the effective reaction with most chemical etchants. However, the photo-enhanced inverse metal assisted chemical (I-MAC) etching, where a noble metal with a high work function is utilized as a catalyst under UV irradiation, has emerged as a candidate for the chemical etching of Ga2O3. Deep-UV irradiation generates electron-hole pairs (EHPs) in the uncovered region of Ga2O3, and the metal electrode withdraws carriers from the photo-generated EHPs. The holes that are accumulated in the uncovered region of Ga2O3 react with gallium ions which produce gallium fluoride (GaF3) in a reaction with Hydrofluoric acid (HF). The etching process continues as the oxidant re-oxidizes the metal. The etch rate can be controlled by various parameter, including concentration and temperature of the etchant. In this work, for the I-MAC etch of α-Ga2O3 on sapphire substrate grown by halide vapor phase epitaxy, Pt was deposited on α-Ga2O3. Etch rate and surface roughness were characterized by atomic force microscopy after each step of the I-MAC etch. The I-MAC etch using HF and potassium persulfate (K2S2O8) solution with 185-nm UV irradiation was performed at constant durations under different etchant temperature conditions. The etch rates obtained at each temperature condition were fitted with the Arrhenius plot to estimate the activation energy of 0.898 eV. The etch depth showed a linear increase with time and the etch rate exhibits a direct dependency on the temperature of the etchant, indicating that the I-MAC etching of α-Ga2O3 is an activation-controlled reaction. As the I-MAC etching proceeded, surface roughness of α-Ga2O3 showed a tendency to increase. The rate at which the surface roughness increased increased with raising the etchant temperature. In the case of Pt there was no significant difference in the surface roughness after etching. After the completion of the I-MAC etch, the remaining Pt can be removed using aqua regia. The I-MAC etch process of α-Ga2O3 can allow us to fabricate α-Ga2O3 without plasma-damage. Figure 1

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Kayede, Emmanuel, Emre Akso, Brian Romanczyk, Nirupam Hatui, Islam Sayed, Kamruzzaman Khan, Henry Collins, Stacia Keller, and Umesh K. Mishra. "Demonstration of HCl-Based Selective Wet Etching for N-Polar GaN with 42:1 Selectivity to Al0.24Ga0.76N." Crystals 14, no. 6 (May 22, 2024): 485. http://dx.doi.org/10.3390/cryst14060485.

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A wet-etching technique based on a mixture of hydrochloric (HCl) and nitric (HNO3) acids is introduced, demonstrating exceptional 42:1 selectivity for etching N-polar GaN over Al0.24Ga0.76N. In the absence of an AlGaN etch stop layer, the etchant primarily targets N-polar unintentionally doped (UID) GaN, indicating its potential as a suitable replacement for selective dry etches in the fabrication of GaN high-electron-mobility transistors (HEMTs). The efficacy and selectivity of this etchant were confirmed through its application to a gate recess module of a deep-recess HEMT, where, despite a 228% over-etch, the 2.6 nm AlGaN etch stop layer remained intact. We also evaluated the proposed method for the selective etching of the GaN cap in the n+ regrowth process, achieving a contact resistance matching that of a BCl3/SF6 ICP process. These findings underscore the applicability and versatility of the etchant in both the electronic and photonic domains and are particularly applicable to the development of N-polar deep-recess HEMTs.

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Çakır, Orhan. "Review of Etchants for Copper and its Alloys in Wet Etching Processes." Key Engineering Materials 364-366 (December 2007): 460–65. http://dx.doi.org/10.4028/www.scientific.net/kem.364-366.460.

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Wet etching processes have been widely used for producing micro-components for various applications. These processes are simple and easy to implement. The selection of suitable chemical solution which is called etchant is the most important factor in the wet etching processes. It affects etch rate and surface finish quality. Copper and its alloys are important commercial materials in various industries, especially in electronics industry. Their wide applications are due to their excellent electrical and thermal conductivity, ease of fabrication, good strength and fatigue properties. The present study examines the possible etchants for copper and its alloys and reviews studies in detail to find out optimum etchant and its application parameters. The study is also aimed to provide information about safety, health and environmental issues caused by using various etchants in wet etching processes of copper and copper alloys.

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Choi, Yongjoon, Choonghee Cho, Dongmin Yoon, Joosung Kang, Jihye Kim, So Young Kim, Dong Chan Suh, and Dae-Hong Ko. "Selective Etching of Si versus Si1−xGex in Tetramethyl Ammonium Hydroxide Solutions with Surfactant." Materials 15, no. 19 (October 5, 2022): 6918. http://dx.doi.org/10.3390/ma15196918.

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We investigated the selective etching of Si versus Si1−xGex with various Ge concentrations (x = 0.13, 0.21, 0.30, 0.44) in tetramethyl ammonium hydroxide (TMAH) solution. Our results show that the Si1−xGex with a higher Ge concentration was etched slower due to the reduction in the Si(Ge)–OH bond. Owing to the difference in the etching rate, Si was selectively etched in the Si0.7Ge0.3/Si/Si0.7Ge0.3 multi-layer. The etching rate of Si depends on the Si surface orientation, as TMAH is an anisotropic etchant. The (111) and (010) facets were formed in TMAH, when Si was laterally etched in the <110> and <100> directions in the multi-layer, respectively. We also investigated the effect of the addition of Triton X-100 in TMAH on the wet etching process. Our results confirmed that the presence of 0.1 vol% Triton reduced the roughness of the etched Si and Si1−xGex surfaces. Moreover, the addition of Triton to TMAH could change the facet formation from (010) to (011) during Si etching in the <100>-direction. The facet change could reduce the lateral etching rate of Si and consequently reduce selectivity. The decrease in the layer thickness also reduced the lateral Si etching rate in the multi-layer.

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Bonyár, Attila, and Péter J. Szabó. "A Method for the Determination of Ferrite Grains with a Surface Normal close to the (111) Orientation in Cold Rolled Steel Samples with Color Etching and Optical Microscopy." Materials Science Forum 812 (February 2015): 297–302. http://dx.doi.org/10.4028/www.scientific.net/msf.812.297.

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Cold rolled steel specimens were investigated by color etching. We proved that in this sample ferrite grains with a surface normal close to the (111) orientation are etched with the slowest speed with Beraha-I type color etchant, and that after a sufficient over-etching these specific grains could be distinguished based on this feature. It was demonstrated, that it is possible to stop the color etching in a phase when only grains with (111) orientation show color due to the layer interference, while all the other grains are dull gray due to a thick and transparent layer. This observation was utilized to develop a method to identify and quantify ferrite grains with (111) orientation in cold rolled steel samples with the application of color etching, optical microscopy and digital image post-processing.

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Kim, Tae Hyeon, Yu Seok Lee, Jong Won Han, and Sang Woo Lim. "Investigation of Oxide Regrowth in the Selective Si3N4 Etching Process for 3D NAND Fabrication by Using Finite Element Modeling Simulation." Solid State Phenomena 346 (August 14, 2023): 143–48. http://dx.doi.org/10.4028/p-e7rksr.

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In the process of manufacturing three-dimensional Not AND (3D NAND) flash memory devices, oxide regrowth occurs during the selective Si3N4 etching process on the Si3N4/SiO2 multi-stack structures. The oxide regrowth issue must be suppressed. Thus, effects of two factors, the mass transfer ability of etching byproduct and the stack number of 3D NAND structure, on oxide regrowth were investigated in this study using finite element method (FEM) simulation. Using FEM simulation, we predicted that increase in the stack number of the 3D NAND structure and decrease in the diffusivity of Si3N4 etching byproducts highly aggravated the oxide regrowth. Therefore, it was suggested that an etchant capable of promoting H2SiO3 diffusion behavior would inhibit the oxide regrowth during the selective Si3N4 etching process of the 3D NAND structure.

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Ki, Bugeun, Keorock Choi, Kyunghwan Kim, and Jungwoo Oh. "Electrochemical local etching of silicon in etchant vapor." Nanoscale 12, no. 11 (2020): 6411–19. http://dx.doi.org/10.1039/c9nr10420h.

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Journal articles on the topic 'Etching'

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