Etching Solution Research Articles

Control of selective SiGe etching by enhanced formation of hydroxyl radicals and by surface passivation in peracetic acid solution

The selective etching of SiGe over Si is a crucial process in the fabrication of advanced 3D semiconductor devices. During the etching process, highly selective SiGe etching is required to obtain precise etch profiles. In this study, the enhancement of the selective SiGe etching in a peracetic acid (PAA) etchant solution by adding hydroxylamine and pentyl acetate was investigated. The addition of hydroxylamine increased the SiGe etching rate and SiGe/Si etching selectivity owing to the more vigorous oxidation of the SiGe surface produced by hydroxyl radicals. The SiGe/Si etching selectivity was also increased through the addition of pentyl acetate owing to the larger decrease in the Si etching rate when compared to that in SiGe. This is due to the stronger passivation effect of pentyl acetate on the Si surface, which suppresses its oxidation more effectively than on the SiGe surface. The SiGe etching rate and SiGe/Si etching selectivity were significantly increased from 223.3 nm/min and 125 to 310.8 nm/min and 557, respectively, through the simultaneous addition of hydroxylamine and pentyl acetate to the PAA etchant solution. Consequently, a mechanism for the selective etching of SiGe on vertically stacked SiGe/Si trench structures using the PAA etchant solution was proposed.

Development of Ge Isotropic Wet Etching Solution and its Application to High Quality Ge-on-Insulator Fabrication through the Etchback Method

Ge has many unique characteristics, such as high carrier mobility and a narrow bandgap corresponding to near-infrared wavelengths. To take advantage of the attractive characteristics of Ge, Ge-on-Insulator (GOI) structures are necessary. In this study, we focus on a direct wafer bonding and etchback method to fabricate GOI structures and explore appropriate etching solutions for the etchback. An HF + H2O2 + CH3COOH solution can isotropically etch Ge and improve surface uniformity. The resulting surfaces were sufficiently flat to achieve Schottky and MOS diodes showing good electrical characteristics of the same level as devices based on commercial mirror-polished Ge surfaces. We discuss the role of the chemicals in the etching solution in achieving the flat surface. We fabricated GOI structures and a back-gate GOI capacitor through direct wafer bonding of SiO2/Si and Al2O3/Ge with the etchback method using the solution. The resulting electrical characteristics are also explained using theoretical calculations. This approach might offer an alternative route to high-quality GOI fabrication.

Influence of Deep Etching Surface Treatment to The Tensile Strength and Microstructure of Brazing Aluminium - Mild Steel

Since hard metals are among the materials that liquid brazing alloys scarcely adhere to, they should not be brazed without first removing the surface layer after sintering. The electrolytic etching method, which gives the surfaces of materials that are hardly wettable very good energetic qualities, is given specific attention. Deep etching is done by using a high concentration of acid solution to roughen the surface. Both dry and wet settings are suitable for etching. An etching fluid is used for etching in a wet environment. Typically, the plate or metal is submerged in an etching solution, where the substance is chemically broken down. While in dry etching, the plasma’s gas phase is where the etching takes place. Due to the presence of plasma in this situation, the etching process that takes place combines chemical and physical processes. Plasma etching is another name for dry etching. Deep etching is an etching process to obtain a rougher surface. Wet deep etching requires a longer immersion time and even several immersions are required. The purpose of this study was to determine the effect of etching treatment in the brazing process of Aluminium-Mild steel for its microstructure and mechanical properties. The specimens in this study used aluminium 6000 series, mild steel, Alusol ER4043, and etching fluid. Mild steel surfaces are deep etched before brazing. Specimen manufacturing standard refers to ASTM D1002. A micro photo test was conducted to compare the surface conditions of aluminium and mild steel with and without etching treatment. The deep etching process is carried out in three variations of time, namely 20, 30, and 40 minutes. The results showed that the tensile strength increased with deep etching treatment on the surface.

Effect of fabrication processes on BaTiO3 capacitor properties

There is an increasing desire to utilize complex functional electronic materials such as ferroelectrics in next-generation microelectronics. As new materials are considered or introduced in this capacity, an understanding of how we can process these materials into those devices must be developed. Here, the effect of different fabrication processes on the ferroelectric and related properties of prototypical metal oxide (SrRuO3)/ferroelectric (BaTiO3)/metal oxide (SrRuO3) heterostructures is explored. Two different types of etching processes are studied, namely, wet etching of the top SrRuO3 using a NaIO4 solution and dry etching using an Ar+-ion beam (i.e., ion milling). Polarization-electric-field hysteresis loops for capacitors produced using both methods are compared. For the ion-milling process, it is found that the Ar+ beam can introduce defects into the SrRuO3/BaTiO3/SrRuO3 devices and that the milling depth strongly influences the defect level and can induce a voltage imprint on the function. Realizing that such processing approaches may be necessary, work is performed to ameliorate the imprint of the hysteresis loops via ex situ “healing” of the process-induced defects by annealing the ferroelectric material in a barium-and-oxygen-rich environment via a chemical-vapor-deposition-style process. This work provides a pathway for the nanoscale fabrication of these candidate materials for next-generation memory and logic applications.

Prediction and analysis etching model of anti-glare glass roughness based on machine learning method

Anti-glare glass, renowned for its exceptional anti-glare properties, has attracted substantial research interest for its wide application in the electronic displays. Glass etching is the key step of the anti-glare glass production, but the formula optimization of this process depends on a numerous factors. In this work, the research focus is on optimizing the composition of etching solution and duration of etching to achieve a desired roughness, recorded at 137.80 nm in our experiment. This study also introduces an innovative approach that integrates experimental etching data with machine learning model predictions. The etch dataset was collected from the experimental etching data, using the etch component and etching duration as the featured inputs, with the resultant glass surface roughness as the target output. Aided by the Random Forest algorithm, how these etching variables influence surface roughness were analyzed and predicted. The accuracy and feasibility of this method are verified by experimental validation, allowing accurate predictions of glass surface roughness. The R2 of the model reaches 0.9165, and RSME is only 22.6690. In addition, the feature importance analysis shows that sorbitol and etching time are the most important factors affecting the roughness, contributing 56.6% and 32.3% to the model’s accuracy, respectively.

ULTRAVIOLET RADIATION DOSIMETRY BY USING OF CN-85 , CR-39, LR-115 NUCLEAR TRACK DETECTORS

Ultraviolet radiation dosimetry was determined by using CN-85 , CR-39 ,LR-115 nuclear track detectors – NTD with measuring of ; number of track-NT , etching time-TB , nuclear track diameter - DT and etching velocity -VD . By this study appear the increasing in etching time-TB of NTD samples which irradiated by UV-radiation do not pure effect on the number of track - NT , comparing with un-irradiated samples . The increasing in UV-irradiation make decreasing in etching time- Topt for CR-39 , CN-85 , LR-115 nuclear track detectors with percent of 20% , 25% , 50% respectively , comparing with un– irradiated sample at the radiation dose 3.77x103 erg /mm2 . . The increasing of irradiation dose make increasing in nuclear track diameter-DT with increase in etching time-TB at the radiation dose 300x103erg / mm2 for LR-115 detector . This study showing there was increasing in the percent value of etching velocity -VB with increasing inradiation dose for CR-39 , CN-85 . The increasing in nuclear track diameter- DTwith increasing in radiation dose was appearing as a resulted of energy of radiationand producted free radicals which interact with chemical etching solution . Thisstudy optioned by using nuclear track detectors CN-85 , CR-39 for determinationthe radiation dosimetry through measuring of etching velocity -VB butter than LR-115 detector

The Effect of Two Etching Solutions NaOH and KOH on Registration Properties and Etching of Polymer CR-39 Detectors

The solid – state nuclear track detector (SSNTDs) CR-39 can be used to study the different factors for alpha particle. Alpha particle is very dangerous inside the human body so the study its very important. In this article, we investigated the impact of two different etching solutions (NaOH and KOH)) on registrations properties, diameter D, track Diameter growth velocity VD, number of tracks and removal layer thickness of CR-39 nuclear track detector. The two types NaOH and KOH were dissolved in water with varied normality (3,5,7,9,11)N under a temperature of (70±1)°C to create the solution. During the experiment, a source of (α-particles) with a 4MeV energy was used to bombard all detectors (30 Sec). It was found the values of the diameter, number of tracks, removal layer thickness, track Diameter growth velocity VD by using the etching solution (NaOH +water) Solution greater than the values in (KOH + water) solution. the results showed excellent agreement with the outcomes of others who utilized different normalities.

Exploring mc‐Silicon Wafers: Utilizing Machine Learning to Enhance Wafer Quality Through Etching Studies

AbstractThis paper provides a method for improving the photovoltaic conversion efficiency and optical attributes of silicon solar cells manufactured from as‐cut boron doped p‐type multi‐crystalline silicon wafers using acid‐based chemical texturization via machine learning. A decreased reflectance, which can be attained by the right chemical etching conditions, is one of the key elements for raising solar cell efficiency. In this work, the mc‐Silicon wafer surface reflectance is obtained under (<2%) after optimization of wet chemical etching. The HF + HNO3 + CH3COOH chemical etchant is used in the ratio 1:3:2 at different conditions of the etching duration of 1 min, 2 min, 3 min, and 4 min, respectively. The as‐cut boron doped p‐type mc‐silicon wafers are analysed with ultraviolet–visible spectroscopy, optical microscopy, Fourier transforms infrared spectroscopy, thickness profilometer, and scanning electron microscopy before and after etching. The chemical etching solution produces good results in 3 min etched wafer, with a reflectivity value of <2%.The reflectivity and optical images are inputs to the convolutional neural network model and the linear regression model to obtain the etching rate for better reflectivity. The classification model provides 99.6% accuracy and the regression model results in the minimum mean squared error (MSE) of 0.062.

An enhanced surface treatment for effective bonding of 7075-T6 aluminium alloys

ABSTRACT This study research focuses on optimising adhesion through surface treatments on 7075-T6 aluminium alloy substrates using a chromium-free protocol. The treatment involves acetone degreasing, NaOH etching, and sulphuric acid-based solution etching. Wettability analysis and scanning electron microscopy were used to characterise the treated surfaces, highlighting the effectiveness of the proposed protocol. The proposed etching protocol was then applied to aluminium alloy substrates, and fracture surfaces corresponding to each treatment were compared. Mechanical testing, specifically double cantilever beam (DCB) experiments, assesses the fracture energy of bonded assemblies in mode I. The results demonstrate that the sulphuric acid-based treatment significantly improves the surface characteristics, leading to enhanced adhesion and optimal fracture energy in bonded aluminium assemblies.

Molten Ba(OH)2.8H2O as an efficient and rapid etchant for detecting α-particles using a diallyl maleate-allyl diglycol carbonate detector

In the present study, for the first time, nuclear tracks of α-particles were created on diallyl maleate-allyl diglycol carbonate (DAM-ADC) using molten hydrated barium hydroxide (MBH). We used 17 DAM-ADC plates with dimensions of 1.0 cm × 1.0 cm × 0.1 cm. The bulk etching rate was calculated at various etching temperatures based on changes in the thickness of the DAM-ADC plates. DAM-ADC was irradiated with α-particles to etch at various temperatures for different durations in order to determine the characteristic etching parameters, such as the bulk and track etching rates, etching efficiency of the detector, and critical angle of etching. Photographs of the etched DAM-ADC samples were obtained with a calibrated optical microscope and analyzed with ImageJ software to calculate the track diameters of α-particles. The results demonstrated that MBH is a more efficient and rapid etchant for registering and detecting charged particles with various energies compared with conventional etching solutions (NaOH, KOH, etc.). DAM-ADC with MBH can be used in environmental applications for detecting radon and neutrons.

Study on the preparation of porous polyethylene glycol terephthalate film and the influencing factors of etching rate

AbstractPorous polyethylene glycol terephthalate (PET) film is a kind of mesopore structure template with pore size ranging from nanometer to micrometer by chemical etching after irradiation of heavy ions. The etching rate is an important factor affecting the pore morphology and quality of the membrane. In this paper, four stacked PET film were irradiated with 140 MeV 32S ions at room temperature and vacuum. During chemical etching of irradiated samples, the path etching rate Vt was determined by conduction method, and the bulk etching rate Vb was determined by weighing method. The relationship between etching temperature, concentration, sensitization time, and etching rate was studied. The results show that the etching rate is exponentially correlated with the etching temperature, and increases linearly with the increase of the etching solution concentration. When the concentration of NaOH is 3 mol·L−1 and the etching temperature is 75°C, the formation of cylindrical micropores is the most favorable. The pore size of porous PET film can be adjusted, and the relationship between pore size and etching time is . This is of great significance for the preparation of nanowires with uniform size and stable properties.Highlights We have obtained the optimal conditions for obtaining cylindrical holes. The relationship between the diameter of holes and etching time were determined.

ОПТИМИЗАЦИЯ ЗАКЛЮЧИТЕЛЬНОГО ЭТАПА ПОДГОТОВКИ ЗУБНОГО ПРОТЕЗА НА ОСНОВЕ ДИОКСИДА ЦИРКОНИЯ К ФИКСАЦИИ ВО РТУ ПАЦИЕНТА

Laboratory study of the acid etching impact on the surface of domestic ceramic translucent zirconium dioxide-based samples by special acid composition has been conducted in order to improve the esthetic qualities of ceramic dentures based on zirconium dioxide as well as to reduce the risk of their breakage and debonding by improving the final treatment methods of the prosthesis surface before fixation in the oral cavity, namely special acid etching of the internal surface and fluorescent glaze applied only to the prosthesis areas visible at a wide smile. The adhesive strength to composite resin cement has been assessed and three different dental fluorescent glazes have been studied for bending strength of zirconium dioxide samples depending on the coating area. The issue of combined effect of the zirconium dioxide-based ceramic’s surface chemical preparation has been studied with a view to increasing both the adhesive strength and the esthetic characteristics. A conclusive reduction in the strength of zirconium dioxide-based ceramic samples after the ceramic coating of each of the studied fluorescent glazes and a significant increase in the adhesive strength of ceramic with composite resin cement after etching with a special composition are shown. To improve the esthetics of zirconium dioxide dental prostheses, prevent the fractures of prostheses and reduce the possibility of their debonding in the oral cavity, it is recommended to apply fluorescent glaze with a minimum sufficient thickness and only on the vestibular and partially occlusal zones, and before fixing to composite resin cement in the oral cavity it is advisable to carry out chemical treatment of the ceramics’ bonded surface with a special etching solution.

Reclamation of acid with electrodialysis process: Influence of selective ion-exchange membranes

Electrodialysis (ED) could concentrate salt solutions, but the leakage of H+ ions across the anion-exchange membrane (AEM) obstructed their application in waste acid recovery. Selective electrodialysis (SED) with acid blocking AEM and monovalent selective cation-exchange membrane (CEM) has the ability of reclaiming acid with high concentration efficiently. This study investigated the individual effect of the two selective ion-exchange membranes by comparing the acid reclamation performance of configurations with standard AEM and CEM (A-C), acid blocking AEM and standard CEM (SA-C) and acid blocking AEM and monovalent selective CEM (SA-SC) for etching solution treatment after diffusion dialysis. Substituting acid blocking AEMs for the standard ones could significantly increase the recovered acid concentration. An acid concentration plateau was reached quickly, but Cu2+ ions transfer through the CEMs continuously due to the low H+/Cu2+ ratio in the dilute of SA-C configuration. The monovalent selective CEM obstructed the migration of Cu2+ through the CEM and broke the balance of H+ migration into and out of the dilute through CEM and selective AEM individually. The configuration of SA-SC has the highest current efficiency and the configuration of A-C has the lowest. The utilization of selective membranes increased the purity of the recovered acid, and decreased the specific energy consumption simultaneously. The acid concentration could be further improved by higher current or enlarged dilute volume in SA-SC configuration. During the ED process, H+ concentration difference between the concentrate and the dilute plays a crucial role on the current efficiency for acid recovery.

A Minimally Invasive Esthetic Approach for Teeth with Molar Incisor Hypomineralization: a Clinical Case Report

Molar incisor hypomineralization (MIH) is a qualitative defect of enamel, clinically characterized by white or yellow/brownish demarcated opacities that affect permanent molars, often associated with permanent incisors. The etiology is multifactorial, including systemic and genetic/epigenetic factors. Defects of anterior teeth can negatively impact children since they might present lower self-esteem and socialization problems. Purpose: To describe a minimally invasive treatment for anterior teeth affected by molar incisor hypomineralization, performed with direct composite resin restoration and a universal adhesive system. Case Report: An 8-year-old patient sought dental care with complaints about her dental appearance, reporting suffering from school bullying. She presented a white-yellowish opacity on the maxillary right central incisor. After a clinical examination, she was diagnosed with molar incisor hypomineralization. To improve dental esthetics, a direct composite resin restoration was proposed. The enamel surface was prepared and etched with 35% phosphoric acid etchant solution for 15 seconds before applying the universal adhesive system. Two different shades of the composite were used for layering the material to disguise the defect without extensive removal of the dental structure. The result was satisfactory as it was possible to mask the opacity, reestablish enamel thickness, and improve the patient's quality of life. Conclusion: Conservative restorations comprising a universal adhesive system seem to bring desirable esthetic results for anterior teeth with molar incisor hypomineralization.

3D nanocubes NiCo-PBA sulfide for high-performance supercapacitors

In this work, 3D nanocubes NiCo-PBA sulfide (NiCoS-PBA) has been prepared by ammonia solution etching and vulcanizing for NiCo-Prussian blue analogue (NiCo-PBA) homemade. The SEM and TEM show that the obtained NiCoS-PBA has the 3D nanocubes structure with rough surface and inward depressions. Electrochemical analysis indicates that an ultrahigh specific capacitance of NiCoS-PBA is 965 C g−1 at 1 A g−1, which is better than that of NiCo-PBA# (256 C g−1), only sulfurized NiCoS-PBA# (369 C g−1) and only etched NiCo-PBA (281 C g−1) at the same condition. This is thanks to the 3D nanocubes structure, which has large accessible areas and rich active sites for redox reactions to enhance the electrochemical performance of supercapacitors. Meanwhile, this also illustrates that the etching and vulcanizing treatments can significantly boost the specific capacitance of NiCoS-PBA. Additionally, the NiCoS-PBA-based asymmetric supercapacitor (ACS) device offers an energy density of 61.7 Wh kg−1 at a power density of 800.1 W kg−1. It is believed that NiCoS-PBA will be a strong contender as an electrode material in supercapacitors.

One-step Cu-assisted chemical etching at room temperature of inverted pyramid array for high-performance crystalline silicon solar cells

Previous studies on the one-step Cu-assisted texturization of silicon wafers have predominantly focused on etching conditions at relatively high temperatures, which are unsuitable for the mass production of solar cells in industrial settings. In this study, we introduced the one-step Cu-assisted chemical etching (Cu-ACE) technique at room temperature to obtain large-area silicon inverted pyramid (IP) array structures. Based on this structure, diamond wire saw (DWS) mc-Si solar cells can achieve a balance between enhanced light trapping and lower carrier recombination by optimizing the concentration of the component Cu(NO3)2/HF/H2O2 in the etchant solution and the etching time during the Cu-ACE process. As a result, these solar cells deliver a power conversion efficiency (PCE) of 18.20 %, which is 1.99 % absolute higher than solar cells using traditional etching techniques. This work paves a new pathway toward the mass production of high-efficiency crystalline Si solar cells, offering a cost-effective and simple texturization approach.

Recyclable fabrication of hollow N-doped amorphous carbon nanospindles with abundant short-range curved carbon fragments as bifunctional anode for lithium/sodium ion storage

A recyclable hard-template method is proposed to exploit spindle-shaped hollow nitrogen-doped amorphous carbon (h-NAC) with a large number of short-range curved carbon fragments as anodes for lithium/sodium ion batteries (LIBs/SIBs). Besides providing adsorption sites due to the high existence of oxygen-containing functional groups (CO and COOH), the heavily exposed edge regions also provide a favorable storage environment with high adsorption energy for Li+/Na+ due to their short-range curved structure. Importantly, the etching solution of hard templates can be recycled to generate the FeOOH nanospindles as a precursor through a simple chemical titration, which supplies a new idea for the green preparation of hollow materials. The h-NAC electrode is proven to be bifunctional for storing lithium and sodium ions, displaying favorable rate capability (255 mAh g−1 and 106 mAh g−1 at 5 A g−1 for LIBs and SIBs, respectively). After 1000 cycles at 1 A g−1, the reproducible capacities of the LIBs and SIBs kept 496 mAh g−1 and 181 mAh g−1, respectively.

EFFECT OF SURFACE TREATMENT ON THE ELECTROCHEMICAL ACTIVITY OF Ti3SiC2/TiC/TiSi COMPOSITE MATERIAL IN THE HYDROGEN EVOLUTION REACTION

The effect of treatment of the surface layer of the Ti3SiC2/TiC/TiSi composite material on its electrochemical activity in the of hydrogen evolution reaction in 0.5M H2SO4 has been studied. Surface treatment has been carried out by chemical etching in solutions of 15, 30, 45% HF for 15, 30, 45 min at 25 and 60 °C. It has been established that the cathodic polarization curves of the Ti3SiC2/TiC/TiSi-electrode without and with surface treatment have a Tafel section with a slope of 0.060–0.076 V and they are characterized by an overvoltage value of 0.20–0.26 V at i = 1 mA/cm2. The rate of the cathodic reaction as a result of treatment increases by ~1.6-9.8 times. The greatest increase is caused by high-temperature etching in a solution of 30% HF for 30 min while stirring the solution. The impedance spectra of the Ti3SiC2/TiC/TiSi-electrode at Tafel region potentials consist of a capacitive semicircle with a displaced center. On the impedance graphs of the treated electrode, a straight section with a slope above 45º was registered in the region of the highest frequencies, indicating the presence of pores in the surface layer of the electrode. To describe the hydrogen evolution reaction on Ti3SiC2/TiC/TiSi, we used an equivalent electrical circuit, the Faraday impedance of which consists of charge transfer resistances R1 connected in series and a parallel R2C2-chain corresponding to the adsorption of atomic hydrogen on the electrode surface. The equivalent circuit also includes the electrolyte resistance Rs and the double layer capacitance impedance, which is modeled by the constant phase element CPE1. It has been shown that the results of polarization and impedance measurements agree satisfactorily with the discharge–electrochemical desorption mechanism with a quasi-equilibrium discharge stage when the logarithmic Temkin adsorption isotherm for adsorbed atomic hydrogen is fulfilled. It has been concluded that the composite material Ti3SiC2/TiC/TiSi in sulfuric acid electrolyte is a promising electrode material for the electrochemical production of hydrogen.

Regeneration of etching solution used in the production of printed circuit boards

Some waste waters containing copper are formed during the production of printed circuit boards. When these effluents are discharged into the reservoir, they must be diluted 140,000 times, and the treatment of these copper-containing effluents causes the copper loosing. The paper presents the results obtained during the study of electrochemical processing of copper-containing effluents formed at the stage of PCBs etching. The spent solution processing was realized in a membrane electrolytic cell. An increase in current density results in an increase in process speed. Along with a decrease in copper concentration in the solution, the hydrochloric acid was concentrated. It is shown that it is possible to regenerate the etching solution and obtain a metallic copper.

Alternative nano-lithographic tools for shell-isolated nanoparticle enhanced Raman spectroscopy substrates.

Chemically synthesized metal nanoparticles (MNPs) have been widely used as surface-enhanced Raman spectroscopy (SERS) substrates for monitoring catalytic reactions. In some applications, however, the SERS MNPs, besides being plasmonically active, can also be catalytically active and result in Raman signals from undesired side products. The MNPs are typically insulated with a thin (∼3 nm), in principle pin-hole-free shell to prevent this. This approach, which is known as shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS), offers many advantages, such as better thermal and chemical stability of the plasmonic nanoparticle. However, having both a high enhancement factor and ensuring that the shell is pin-hole-free is challenging because there is a trade-off between the two when considering the shell thickness. So far in the literature, shell insulation has been successfully applied only to chemically synthesized MNPs. In this work, we alternatively study different combinations of chemical synthesis (bottom-up) and lithographic (top-down) routes to obtain shell-isolated plasmonic nanostructures that offer chemical sensing capabilities. The three approaches we study in this work include (1) chemically synthesized MNPs + chemical shell, (2) lithographic substrate + chemical shell, and (3) lithographic substrate + atomic layer deposition (ALD) shell. We find that ALD allows us to fabricate controllable and reproducible pin-hole-free shells. We showcase the ability to fabricate lithographic SHINER substrates which report an enhancement factor of 7.5 × 103 ± 17% for our gold nanodot substrates coated with a 2.8 nm aluminium oxide shell. Lastly, by introducing a gold etchant solution to our fabricated SHINER substrate, we verified that the shells fabricated with ALD are truly pin-hole-free.