bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multicomponent Layer-By-Layer Films of Chitosan/Phthalocyanine/AuNPs As Biosensing Platforms
Authors: Rodriguez-Mendez Maria Luz , Salvo-Comino Coral , Perez-Gonzalez Clara , Martin-Pedrosa Fernando , Garcia-Cabezon Cristina 
Published: July 2021

The search of new biosensing platforms is crucial to improve the performance of electrochemical biosensors. In this work, Layer by Layer films containing combinations of materials with different functionalities were used to design electrochemical biosensor platforms for phenols detection [1-3]. Catechol and hydroquinone biosensors were obtained by depositing tyrosinase (Tyr) or laccase (Lac) on the surface of LbL films formed by alternating layers of chitosan (CHI), a cationic species which acted as enzyme linker, and layers of two anionic electrocatalytic materials (sulfonated copper phthalocyanine, CuPcS and citrate capped gold nanoparticles, AuNPs). Films with different sequences [(CHI)-(AuNPs)]2, [(CHI)-(CuPc)]2, [(CHI)-(CuPc)-(CHI)-(AuNPs)]2 [(CHI)-(AuNPs)-(CHI)-(CuPc)]2, and [(CHI)-(AuNPs/CuPc)]2 (with CuPcS and AuNP mixed in the same layer) were characterized by UV–visible, FTIR spectroscopy and AFM.
It was demonstrated that the resulting films provided an efficient immobilization surface for phenol oxidases. At the same time, the LbL platform improved the electron transfer between the enzymes and the electrode surface. Although all the biosensors obtained exhibited excellent performances, the sequence of the anionic and cationic layers strongly influenced the electron transfer process. The best results were obtained when CuPcS was present in the last layer which caused a 2-fold increase in the intensity over the response of the biosensor without the LbL platform. The [CHI-AuNP-CHI-CuPcS]2-Tyr bioelectrode showed an LOD of 8.7∙10-4 mM (S/N=3) for catechol and of 7.77∙10-4 mM (S/N=3) for hydroquinone. The LbL platform was not so efficient for laccase and the [CHI-AuNP-CHI-CuPcS]-Lac biosensor showed a LOD of 1.84∙10-2 mM (S/N=3) for catechol and of 1.27∙10-3 mM (S/N=3) for hydroquinone.

References

[1] C. Medina-Plaza, L.N. Furini, C.J.L. Constantino, J.A. De Saja, M.L. Rodriguez-Mendez, Synergistic electrocatalytic effect of nanostructured mixed films formed by functionalised gold nanoparticles and bisphthalocyanines, Anal. Chim. Acta. 851 (2014) 95–102. doi:10.1016/j.aca.2014.08.049.
[2] C. García-Hernández, C. García-Cabezón, F. Martín-Pedrosa, J. A. De Saja, and M. L. Rodríguez-Méndez, Layered composites of PEDOT:PSS/nanoparticles and PEDOT:PSS/phthalocyanines as electron mediators in sensors and biosensors, Belstein J. Nanotech. 7 (2016) 1948-1959
[3] E. G. R. Fernandes, L.C. Brazaca, M.L Rodríguez-Méndez, J.A. de Saja and V. Zucolotto, Immobilization of Lutetium Bisphthalocyanine in Nanostructured Biomimetic Sensors Using the LbL Technique for Phenol Detection, Biosens. Bioelectr. 26 (2011) 4715- 4719.

Acknowledgements

Financial support by MINECO-FEDER (RTI2018-097990-B-I00) and the Junta de Castilla y Leon FEDER (VA275P18) and AFM UVA01is gratefully acknowledged.
In-Situ Corrosion Screening of Co-Sputtered (Fe-Cr-Ni) Alloy Thin Film Library in Simulated Human Physiological Condition
Authors: Lone Shaukat Ali , Mardare Cezarina Cela , Mardare Andrei Ionut , Hassel Achim Walter 
Published: July 2021

High throughput combinatorial analysis is a cost effective and time saving approach for characterizing a wide range of alloys. This technique can be used to optimize the chemical composition for several applications i.e. corrosion resistance and pharmaceutical[1-2]. Austenitic stainless-steel (AISI 316L and ASTM F-55) exhibits excellent load bearing and tribocorrosion resistance in human body condition[3]. However, these alloys have shown ineffectiveness to resist the localized form of corrosion and harmful release of metallic ions i.e. Ni, Cr and Fe in the human body[4].
Hereby a ternary library with a compositional matrix of Fe (59-86 at.%), Ni (3-15 at.%) and Cr (9-30 at.%) is produced through co-sputtering. All compositions exhibited a columnar grain structure with pointy tips. The grain size ranged between 10-50 nm. Broad peaks corresponding to respective (110) and (211) planes of rt Fe (BCC) were detected in XRD patterns. These peaks were tentatively assigned to the solid solution of Fe with Cr and Ni. All electrochemical experiments were undertaken in Ringer’s solution at 37 oC by means of an in house-built flow type scanning droplet cell microscope. Additionally, the used electrolyte was analyzed by inductively coupled plasma optical emission spectroscopy (ICP-OES). It was observed that as the Fe concentration increases more than 82 at.%, the preferential dissolution of Fe occurred continuously during cyclic voltammetry experiments. Simultaneously, Cr exhibited a surface enrichment (non-congruent dissolution) at all concentrations, but a minimum of (14-16 at.%) is required to behold the significant passivity. Interestingly, no metal was detected above detection limit during cyclic voltammetry for the alloys with compositions containing Ni > 11 at.% and Cr > 20 at.%. This work shows the influence of each constituent (Fe, Ni and Cr) on the passivity of Fe-Cr-Ni ternary system. Hence, it can also be perceived as a guideline for the surge of better performing Fe-Cr-Ni ternary alloys as a biomedical implant.
References
[1] Natalia Pimenova and Thomas Starr, Electrochemical Corrosion Investigation of 49-Cell Combinatorial Library of Titanium-Based Alloys Fabricated by DMD, J. Electrochem. Soc, 155, 303-305, (2008); DOI: 10.1149/1.2899021.
[2] John Murphy, Tetsuo Uno, Janice Hamer, Fred Cohen, Varavani Dwarki, Ronald Zuckermann, A combinatorial approach to the discovery of efficient cationic peptoid reagents for gene delivery, PNAS, 95, 1517-1522, (1998); DOI:10.1073/PNAS.95.4.1517
[3] M. Sumita, Y. Ikada, T. Tateishi, Metallic Biomaterials Fundamentals and Applications, ICP, Tokyo, 629 (2000).
[4] M. Sumita, Present status and future trend of metallic materials used in orthopedics, Orthop. Surg, 48, 927 (1997).
Monitoring Coating System Changes Using Equivalent Circuit Fit Parameters
Authors: Policastro Steven , Anderson Rachel , Hangarter Carlos M , Arcari Attilio , Iezzi Erick 
Published: July 2021

Organic coating systems are used to manage the corrosion of metal surfaces subjected to atmospheric degradation. These coating systems are frequently complex and multilayered and capable of providing several functions, including: substrate adhesion, corrosion inhibition and electrolytic barriers. In addition, the service environment can be equally complex with exposure to UV radiation, wet/dry cycling, and application of thermal and physical stresses on the substrate and coating system alike.
Refining our ability to predict service life and explain how these coatings evolve over the course of their lifetimes provides an opportunity to decrease maintenance costs and aid in future coating development. These objectives can be achieved by the development of predictive models that incorporate the fundamental effects of relevant service environment parameters. This would provide reliable damage predictions based upon the measured environmental data thereby decreasing our dependence on proxy corrosion sensors.
To that end, the first phase of this project has focused on testing and monitoring an aircraft coating system that is comprised of a surface pretreatment, an epoxy primer with inhibitors, and a polyurethane topcoat exposed to a variety of degradation conditions that simulate the extreme ranges of environmental stresses expected to be seen in-service. Coating condition was monitored using electrochemical impedance spectroscopy (EIS) and characterized with equivalent-circuit models so that changes to the coating system properties could be quantified and tracked over time.
Regression models for the changes in the coating system properties are being developed and will be validated by follow-on outdoor exposure testing in the next phase of the program.

Acknowledgments

The Department of Defense Strategic Environmental Research and Development Program (SERDP) sponsored this work under program WP19-1017. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of the Office of Naval Research, the U.S. Navy, or the U.S. government.
Barrier and Packaging Level CMP Optimization
Authors: Basim G. Bahar , Sur Debashish , Langhout John 
Published: July 2021

The yield of chip packaging operations is a function of the surface finish that is solderable and wire-bondable. It has been shown that the use of palladium (Pd) plated lead-frame for packaging has improved the processing cost and reliability by simplifying the process integration [1]. Pd can also be used as a sacrificial layer to protect the copper (Cu) substrate material from oxidation and interdiffusion before the SnPb solder application. In packaging applications, Pd is advantageous in forming a Ni(Pd)Si allowing a lower sheet resistance at higher temperatures as compared to the NiSi in addition to much better surface morphology [2].
The new integration schemes of Pd into the circuitry at the packaging level also require a CMP application where the Pd is deposited on the dielectric layer with bond-pad recess and polished to form a Pd based pad surrounded by Ni [3]. In combination with the applications of the 2.5 and 3-D microelectronics packaging technologies, the CMP electivity becomes critical where a competitive removal rate is desired between the Cu, Cu-barrier (TaN) and Ni films
It has been demonstrated on W-CMP in an earlier study that the 1:1:1 removal rate selectivity of the W/Ti/TiN layers can be achieved through adjusting CMP formulations in terms of the slurry chemistry and the particle concentrations. The systematic study has demonstrated a methodology for developing optimal CMP configurations for the newly introduced films to CMP applications based on electrochemical evaluations [5].
In this paper, we study the removal rate selectivity for Pd integrated packaging level CMP applications through electrochemical and surface energy evaluations in commercial bulk and barrier CMP slurries. It can be seen that the thin film dissolution rates relate to the surface passivation as well as the surface energy measured by the contact angle evaluations on the Cu, Pd, TaN and Ni wafer coupons. Pd being a novel metal shows strong passivation that results in minimal dissolution in the slurry environment which requires alternative formulations for CMP slurries to promote the removal rate performance.
References:

Kajija, I.V., Absy, J.A., Maisano, J.J., Kudrak, A.J., Shimada, S. “Thin Multilayer Palladium Coating for Semiconductor Packaging Applications. Part I: Solderability. NASF Surfcae Technology White Papers, 80 (6), 6-19 (2016).

Karabko, A., Dragasius, E. Nisi and Ni(Pd)Si as possible interconnect and electrode material for film bulk acoustic resonators and microelectromechanical systems. Journal of Vibroengineering, 15 (1), 2013.

Eisa, M., Zinn, B. “Aluminum Enhanced Palladium CMP Process” US Patent 8,288,283, October 16, 2012.

Song, C., Wang, Z., Chen, Q., Cai, J., Liu, L. “High aspect ratio copper through-silicon-vias for 3D integration”, Microelectronic Engineering, 85 (10), P1952-P1956,

Yagan, R., Basim, G.B., “A Fundamental Approach to Electrochemical Analyses on Chemically Modified Thin Films for Barrier CMP Optimization," ECS J. Solid State Sci. Technol. 8-5, P3118-P3127, 2019.
Effect of Radial Groove Pad on Copper Chemical Mechanical Polishing
Authors: Bae Chulwoo , Oh Shinil , Kim Taesung 
Published: July 2021

Chemical mechanical polishing (CMP) is a process that reduces step height by making the flat surface when several types of layers are accumulated in a semiconductor device. The three main factors affecting CMP are pad, slurry and conditioner. Among these factors, the pad helps the flow of the slurry and polish the wafer with direct contact. Through changing characteristic of pad that is number of grooves, design of groove, depth and width of pitch, we can control wafer removal rates, with-in wafer non-uniformity and roughness.
In this study we added a radial groove (RG) at the circular groove (CG) pad to investigate what effect of the RG to Cu CMP. A study was conducted on how the number of RG affects the slurry flow, how changes in slurry flow affect the pressure distribution between the pad and the wafer, and how this affects CMP. The number of RG was divided into 0, 8, 16, 32, and the actual CMP process and simulation experiment were conducted together. In simulation part, we use computational fluid dynamics (CFD) to compare for slurry transport rates according to the number of RG. Fig. 1 shows the removal rates according to the number of RG, and when the number of RG increases to 32, it shows that removal rates of RG pad is almost 23% higher than CG pad. We consider that these results are related to changes in slurry flow during polishing. This is due to role of RG in quickly replacing the old slurry with the new slurry.

Figure 1
Multiple Technique Characterization of the Physical and Chemical Properties of Silica Abrasives Used in Chemical-Mechanical Planarization
Authors: Moinpour Mansour , Vacassy Robert , Kamiti Mungai , Campbell Kristine , Jones Evan , Remsen Edward 
Published: July 2021

The performance of chemical-mechanical planarization (CMP) slurries in the commercial fabrication of integrated circuits depends critically on the physical and chemical properties of abrasive particles used in CMP slurries. A host of analytical methods are used for characterizing the properties of CMP abrasive particles including spectroscopic,1,2 sedimentation,3 viscometric4 and fractionation5 techniques. One particular method, fluorescence correlation spectroscopy (FCS),1 has demonstrated significant versatility in this application due to its ability to simultaneously analyze the particle size distribution and the surface chemistry of abrasive particles in aqueous mixture containing small molecule CMP additives. The need for further characterization of these properties, especially the surface chemistry, is the product of the increasing use of nano-abrasives with reduced hydrodynamic diameters (< 20 nm) in CMP slurries in order to minimize surface defect creation during CMP processes. Incorporation of nano-abrasives in CMP slurries will promote surface chemistry-driven CMP additive adsorption on abrasive particles due to the increase in the total particle surface area as the hydrodynamic diameters of nano-abrasives decrease. The use of FCS in conjunction with the application of complementary techniques, such as dynamic light scattering and fluorescence lifetime analysis, is described in the presentation for the comprehensive characterization of the physical and chemical properties of representative silica abrasives used in CMP slurries.
1. Jacobson, L.M.; Turner, D.K.; Wayman, A.; Rawat, A.; Carver, C.T..; Moinpour, M.; Remsen, E.E. “Characterization of Particle Size and Surface Adsorption for SiO2 Abrasives Used in Chemical Mechanical Planarization via Fluorescence Correlation Spectroscopy”, ECS J. Solid State Sci. Tech.
2015,
4, P5053-P5057.
2. Marsh, J.L.; Wayman, A.E.; Smiddy, N.M.; Campbell, D.J.; Parker, J.C.; Bosma, W.B.; Remsen, E.E. “Infrared Spectroscopic Analysis of the Adsorption of Pyridine Carboxylic Acids on Colloidal Ceria”, Langmuir
2017, 33
, 13224-13233.
3. Kamiti, M.; Boldridge, D.; Ndoping, L.M.; Remsen, E.E. “Simultaneous Absolute Determination of Particle Size and Effective Density of sub-Micron Colloids by Disc Centrifuge Photosedimentometry”, Anal. Chem.
2012,
84, 10526−10530.

4. Boldridge, D.; Kamiti, M.; Remsen, E.E. “Avoiding the Spherical Particle Assumption: Fractal Particle Density, Size and Structure Characterization through Combined Sedimentation and Viscometry Measurements”, Anal. Chem.
2020, 92, 15034-15041.
5. Williams, S.K.R.; Park, I.; Remsen, E.E.; Moinpour, M. “New Particle Metrology for CMP Slurries”, Mater. Res. Soc. Symp. Proc. 2007,
991, 249-251.
Development of Particle Detecting Technology for Measurement Slurry Particle Property in Chemical Mechanical Polishing Process
Authors: Kim Chang min , Park Kihong , Jeon Sanghcuk , Kim Taesung 
Published: July 2021

Recently, particle size and analysis technology are used for various industry filed and become very important. Because small particle can affect to manufacture process and product yield. Especially. As design rule of semiconductor device is miniaturizing to 10 nm class. Because of this, very fine particle which size is below 100 nm can affect to the wafer as shown Fig. 1. In addition to this, after chemical mechanical polishing (CMP) process many defects can occur by fine particles in CMP slurry which are remain on the wafer. In this reason, we need a technology which is measure the particle property of slurry in CMP process.
In this study, particle detecting technology has been investigated which is can detect a particle in the CMP slurry for wafer polishing. In this experiment, single particle sizing system (SPOS) is used for particle detecting in CMP slurry. The SPOS system is a single particle detecting system which system is the principle of measuring scattering light generated by particles. It can get a high resolution from detecting a small size particle also analysis of particle property such as size, shape and so on.
Fig, 2 shows a schematic of the experiment set-up and result, which experiment was consisting of five devices that is He-Ne laser, laser power meter, tubing pump and lens system. The experimental principle is firstly preparing the solution which contain particles to flow the quartz tube. Second, prepare the focusing and collecting lens system. Third, aligning the laser to the quartz tube where the solution flows and turning it on will cause the laser light to hit the particles present in the solution, which will measure the scattered light with a laser power meter.

Figure 1
First Principles Study of Reactions in Hybrid Film Growth: The Role of the Organic Precursor
Authors: Muriqi Arbresha , Nolan Michael 
Published: July 2021

Hybrid materials are a special class of materials with tunable features. This is related to their diphasic structures that leads to multifunctional materials with a wide range of applications. Molecular layer deposition (MLD) enables the fabrication of ultrathin and conformal hybrid films using sequential, selflimiting reactions, similar to ALD. Despite growing interest in these materials, there is little understanding of the atomistic mechanism of MLD film growth.
In this contribution, we explore the molecular mechanisms of the growth of different hybrid organic−inorganic thin films by using density functional theory (DFT). The prototype for MLD organic−inorganic hybrids are composed of thin films of aluminium alkoxides, known as ”alucones”. We investigate the MLD reaction products between the post-TMA Monomethyl-Al2O3 (Al-CH3-Al2O3) and Dimethyl-Al2O3 (Al(CH3)2-Al2O3) surface and the organic precursors ethylene glycol (EG) and glycerol (GL). The DFT calculations show that while the organic precursors can bind to the TMA fragments via formation of Al-O bonds and loss of CH4, it is most favorable for the organic precursors to lie flat and create so-called double reactions through two terminal hydroxyl groups with the surface fragments, where the terminal groups bind to Al. For EG this potentially removes all the active sites and growth will be less favorable. For GL the third hydroxyl group is available and growth can proceed. We also showed that the TMA in the next pulse reacts favourably with this OH from GL.
We also explored the growth mechanism of magnesium containing hybrid films known as “magnesicone” from the reaction of EG and GL at MgCp-terminated MgO(100) as a model system. Interaction energies presented some clear differences in reaction mechanism of films grown with EG and GL. While the ligand elimination process is favorable for both precursors, EG prefers to orient in a flat configuration and interacts at the MgO(100) surface and GL species prefers to lie in an upright position. As a consequence the change in thickness for GL-based process is larger than for EG-based process, resulting in a thicker GL-based magnesicone compared to the EG-based magnesicone.
Finally we use DFT to explore the growth mechanism of titanium-containing hybrid organic−inorganic films known as “titanicones”. We investigate the reaction mechanism of titanicones grown using titanium tetrachloride (TiCl4) as metal source and either ethylene glycol (EG) or glycerol (GL) as organic reactants. This investigation contributes to the understanding of growth process of EG and GL based hybrid films at the molecular level and is valuable in supporting experimental data on hybrid film growth.
(Invited) Novel Chemistries for Layer-by-Layer Etching of 2D Semiconductor Coatings and Organic-Inorganic Hybrid Materials
Authors: Elam Jeffrey W. , Mane Anil U. , Young Matthias J. , Choudhury Devika , Letourneau Steven , Yanguas-Gil Angel 
Published: July 2021

Here we report two new advances in atomic layer etching (ALEt) that extend our range of capabilities in nanoscale device fabrication. Semiconductor device manufacturing is limited by our ability to precisely deposit and remove thin film layers at the various levels of multistep device fabrication processes. Consequently, innovations in atomic layer deposition (ALD) and etching methods are essential. ALD-based methods have matured significantly and are now used extensively in semiconductor fabs. Recently, there has been an intense focus on developing ALEt methods. In particular, thermal ALEt has been shown to precisely remove ALD inorganic thin films selectively and on complex structures. These capabilities have opened new possibilities for nanoscale device design. Here, we report a new thermal etching process similar to ALEt for removing hybrid inorganic-organic layers that we call molecular layer etching (MLEt). This MLEt process uses vapor phase lithium organic salts in combination with trimethyl aluminum to perform layer-by-layer etching of molecular layer deposition (MLD) coatings.
Ultra-thin layers of two dimensional (2D) transition metal dichalcogenide (TMD) semiconductors can exhibit exceptional electrical, optical, magnetic, mechanical and chemical properties. This allows the exploration of internal quantum degrees of freedom of electrons and their potential application in optoelectronic, energy, and sensor devices. Among the various 2D-TMDs, MoS2 has shown exciting material properties and this has stimulated the exploration of a variety thin film synthesis methods such as physical vapor deposition (PVD), chemical vapor deposition (CVD), and solution based methods. In addition, the ALD community is investigating ALD methods for MoS2 growth. Here we report the thermal ALEt of ALD MoS2 thin films. We believe the successful combination of both ALD and ALEt of MoS2 and other TMDs can pave the way to control the synthesis of 2D-TMD layers over large areas. Combining ALD and ALEt will allow MoS2 interface engineering and enable MoS2 integration into the large-scale manufacturing of future complex device structures.