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Tungsten trioxide (WO₃) thin films are very well known for their efficient electrochromic properties under the double insertion and extraction of various suitable ions and electrons. Although both the amorphous and polycrystalline WO₃ thin films exhibit an efficient coloration in the visible and nearinfrared spectral regions from an initial transparent state under the double insertion, the underlying phenomenon leading to this coloration is quite different. In the amorphous films it is the absorption modulation while it is reflectance modulation in the polycrystalline state. In the former case, the coloration takes place due to the intervalence transfer of electrons from one site to the other in the mixed valence WO₃ films through the absorption of light (polaron absorption). However, the coloration in the polycrystalline films is due to the reflectance arising from the free electrons injected into the host material (plasma frequency edge displacement). However, in most commonly used deposition conditions in which a polycrystalline film is expected to be formed, it can be surmised that the WO₃ film is composed of polycrystallites held in an amorphous host material. This leads to an electrochromic coloration arising from a combination of absorption and reflectance modulation. In the present work, we have undertaken a systematic study of the electrochromic evolution of WO₃ films deposited under different conditions and subjected to dry lithiation using lithium niobate (LiNbO₃) powder under controlled heat treatment. The structural, electrical and optical properties of the as-deposited and colored films have been measured using an Atomic Force Microscope (AFM), four-point probe and a UV-Vis-NIR double beam spectrophotometer. Hall effect measurements have been carried out to calculate the free electron density (ne) inserted into the WO₃ film and correlated with the effective lithium film thickness measured by quartz crystal method. Preliminary results of this work are presented here.

https://doi.org/10.14332/svc24.proc.0007

Due to the potential of excellent film control, uniformity, and conformality, atomic layer deposition (ALD) is seen as very promising for quantum devices where interface and material quality and their uniformities are a big challenge. Furthermore, for superconducting circuits, the deposition rate of ALD can be an issue since sufficient film thickness (> 50 nm) is needed to minimize kinetic inductance effects on resonator frequency and the shielding effectiveness of superconducting vias for crosstalk mitigation depends on film thickness and film conformality in the 3D structures. The challenge here is to deliver a sufficiently fast processes while maintaining the desired film properties and benefits of ALD.
Here, we will share our recent development of a new remote plasma ALD system providing high-quality superconducting NbN and TiN for quantum applications at rates > 25 nm/hour, which is approximately 3x faster than previously reported. The RF-driven remote plasma source design and chamber of our ALD system are optimized to enable this high deposition rate.
The quality of the deposited films was demonstrated to be excellent, as measured by four-point probe electrical resistivity, conformality (100% on 8:1 trench for NbN, verified by SEM), and superconducting transition temperature (Tc). Good superconducting properties of the film were demonstrated by SQUID measurements. A thickness non-uniformity of < ±5% across a 150 mm Si wafer was achieved with good repeatability. Both NbN and TiN films show cubic crystalline structure as confirmed by XRD measurements. We will also show how stress can be tuned as a function of process parameters, such as the RF source power and discuss film composition, stoichiometry and purity levels such as carbon and oxygen. We will also touch upon how ALD is well-suited to combine processes and provided ternary films such as NbTiN.
Emerging quantum technologies based on superconducting nitride materials are showing great promise and will benefit not only from the uniformity of the deposition, conformality and film quality, but also from the speed and control provided by ALD processes on this system.

https://doi.org/10.14332/svc24.proc.0001

Complex systems for coatings, deposition and etch often require precise temperature measurement and control for improved product yields. Other critical parameters may include process pressures, gas line temperatures and chamber wall temperature or strain as a safety concern. Cost-effective, field-proven fiber optic sensing solutions provide significant advantages over other sensor technologies in these demanding environments.
Fiber optic sensors are inherently immune to electromagnetic interference from RF, induction, and microwave sources. They can also be shielded from plasma light interferences to provide stable and accurate measurements. No sensor calibration is required over the design lifetime with minimum fatigue, resulting in lower cost of ownership. Multiple sensors and mixed sensing parameters, such as temperature and strain/pressure can be used on a single fiber optic cable thus reducing the complexity of installations and greatly increasing the density of measurement points. In addition, the fiber optic sensors are ideally suited for ALD and Etch applications, providing excellent accuracy from cryogenic temperatures to 450°C. In this presentation, Advanced Energy will review the status of fiber optic sensor technologies including phosphor decay, Fiber Bragg Gratings, Fabry Perot interferometry and infrared fiber pyrometry, followed by highlights of application solutions for ALD, PECVD and Plasma Etch systems including installation and performance advantages of these sensors.

https://doi.org/10.14332/svc24.proc.0002

Metal oxide thin films with antibacterial properties can be deposited via atomic layer deposition (ALD) on the surface of neurostimulation and cardiac rhythm management electrodes to prevent risks of post implantation infections and bacteria colonization. In this work, we report on the development of antibacterial platinum-iridium electrodes using a two-step process. Electrodes are first hierarchically restructured using femtosecond-laser hierarchical surface restructuring technology and then ALD is used to deposit ultrathin metal oxides of ZnO on hierarchically restructured electrodes. Structural, chemical, and mechanical properties of ZnO films were studied using X-ray diffraction, X-ray photoelectron spectroscopy, energy dispersive X-ray spectroscopy, scanning electron microscopy and nanoindentation. The antibacterial properties of the ALD-coated electrodes were also studied, particularly, the killing effect on the two common types of bacteria (E. coli and S. aureus) responsible for implantation infections.

https://doi.org/10.14332/svc24.proc.0005

As greater demands are placed upon manufacturing, coatings by physical vapor deposition (PVD), chemical vapor deposition (CVD) and plasma-assisted CVD (PACVD) are in many cases essential to increase productivity and to ensure excellent product quality while minimizing production downtime and scrap rate in forming and molding tool applications.
CrN coatings with and without the addition of tungsten remains an excellent choice for many forming applications. However, the wear properties at elevated temperatures under certain tribological conditions, such as observed in high temperature Pin on Disking (POD) Testing can be improved.
One approach that can be used to improve the high temperature tribology of CrN is to deposit a Cr_xO_y or (CrW)_xO_y top layer over CrN or CrWN, respectively.
This paper details the investigation of the tribological properties at room temperature, 400°C, 600°C and 800°F of CrN + Cr_xO_y as well as CrWN + (CrW)_xO_y deposited in commercial PVD arc chambers. The industrial applications where such coatings have benefited are in certain hot forging, die casting, and plastic molding applications.

https://doi.org/10.14332/svc24.proc.0042

Single-component metal oxide films of alumina (Al₂O₃) and silica (SiO₂) grown by atomic layer deposition (ALD) have been well-characterized for their barrier properties. Neither SiO₂, nor Al₂O₃ exhibit robust barrier performance individually, but it has been previously shown that combining those binary oxide films to form ternary oxide (AlSiO) improves barrier performance, particularly in resilience to damp heat conditions. Previous methods for creating ternary metal oxides have been achieved by alternating layers to create nanolaminate structures, or by alternating ALD cycles between the two materials to create a homogeneous mixture. In this work, aluminum and silicon precursors are simultaneously co-delivered in a single vapor stream to grow a homogeneous mixture of AlSiO via a process that exhibits well-behaved, tunable composition control. It is shown that mixing these constituents within a specific compositional range results in optimal barrier performance, even in exposure to damp heat. This ALD process, featuring spatial precursor separation and plasma-enabled oxidation, provides a path to high-speed deposition at low substrate temperatures for growth of thin ultra-barrier coatings in batch, sheet-to-sheet, and roll-to-roll platforms.

https://doi.org/10.14332/svc24.proc.0003

Touch surfaces play a crucial role in the transmission of bacteria and pathogens, especially in hospital and healthcare settings. There are many pathogens which are commonly found in patient wards and public areas throughout hospitals that lead to Hospital Associated Infections (HAI) which can have a devastating effect on the physical, mental, and financial health of a patient. In addition to this, HAIs cost the healthcare system billions of dollars a year in added expenditure. Furthermore, it has been found that a growing number of the pathogens detected have become resistant to the antimicrobial medications typically used to control them.
This work presents novel magnetron sputtered coatings have been developed with very high levels of biocidal efficacy. Sputtered antimicrobial surfaces have been produced in industrial PVD systems, including box coaters and Roll-to-Roll machines. 2D and 3D components were coated, as well as transparent flexible films. The surfaces have been deployed in the Royal Liverpool University Hospital in the United Kingdom. Flexible films were adhered to patient self-check in kiosks, and push pads and handles were installed throughout busy wards. This paper presents results from standard antimicrobial tests conducted over a 24-hour period, and long term data acquired during the regular monitoring of the surfaces.

https://doi.org/10.14332/svc24.proc.0065

With antimicrobial resistance, hospital acquired infections, and device-associated infections all on the rise, the need for novel approaches to antimicrobial treatments and materials is of significant need in the biomedical field. Research endeavors across multiple disciplines have been addressing this issue from various perspectives including traditional small molecules, peptides, proteins, polymers, probiotics, phage, and combinatorial approaches. Vacuum approaches, such as sputtering and other physical vapor deposition techniques, have been evolving to make coatings with bactericidal characteristics. Antimicrobial surface development has been an area of great interest for materials and devices and have also involved numerous specific functional modalities.

Our team has focused on the development of metal based, thin film coatings for medical device applications, specifically bone/joint implants, and electrostimulation devices. Testing the bactericidal activity of these vacuum applied coatings require modifications to traditional biochemical testing techniques. After modifying the testing techniques, we have shown that these coatings demonstrate remarkable broad-spectrum antimicrobial activity, high bioavailability of the active compounds to interact with bacterial targets, minimal cytotoxicity, and retention of conductivity properties essential in electrostimulators. The coatings are versatile, with significant tunability to tailor the active component release profiles to the application of the material.

Our current approaches and results will be discussed, with a focus on the antimicrobial methodology used to evaluate the efficacy of antibacterial activity specifically on vacuum applied coatings. These techniques will also be discussed regarding their potential role in the investigation of nature-inspired topographies controlling biofilm adhesion. In general, these updated or modified assays will be discussed to describe how they can interact and synergize with traditional surface/materials characterization approaches to enhance the understanding of antimicrobial mechanisms.

https://doi.org/10.14332/svc24.proc.0004

This presentation will discuss the importance of leveraging federal government resources to support the launch of new (start-up) technology, Specifically, National Science Foundation (NSF) Industry-University Cooperative Research Centers (IUCRC) for low-cost start-up development. It will highlight the advantages of collaborating with these centers, including access to state-of-the-art research facilities, expertise from leading researchers, and potential funding opportunities. The presentation will also present a case study of a successful start-up that has utilized NSF centers to drive innovation, growth, and funding. Additionally, it will provide practical tips and strategies for start-up founders on how to navigate and effectively leverage these valuable resources. By sharing insights and lessons learned, this presentation aims to inspire and empower entrepreneurs to take advantage of the vast opportunities offered by NSF Industry-University Cooperative Research Centers (IUCRC) and other forms of Federal Grant programs such as DOE/DOD funding for their start-up development.

https://doi.org/10.14332/svc24.proc.0009

With a goal to assess the efficiency of physical vapor deposition (PVD) coating defect sealing by atomic layer deposition (ALD layers, we investigated the corrosion resistance of PVD TiN and TiN + ALD Ti-O (amorphous and anatase) layers in Hank’s solution. The corrosion experiments were conducted on circular areas with 2 mm radius, employing electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PD) measurements. To identify defect types, quantities, and their dimensions, confocal and tactile profilometry were performed before and after the corrosion tests. Results revealed that corrosion resistance of layers is influenced by the quantity of through-thickness “critical” defects. The above-coating height of these defects is approximately half of the coating thickness, and their diameter is proportional to the coating's thickness. With an increase in their quantity the corrosion resistance of a coated system decreases. Scanning electron microscopy (SEM) of the focused ion beam (FIB) milled cross-sections revealed a uniform surface coverage by both ALD layers and effective defect sealing. Therefore, application of ALD layer over the PVD coatings emerges as a highly effective strategy for enhancing their corrosion resistance. Additionally, SEM and atomic force microscopy (AFM) analysis of a hybrid layer with anatase TiO₂ revealed formation of protruding nano-features on the surfaces. Such features have promising effects on the bone-cells activity and increased implant osseointegration.

https://doi.org/10.14332/svc24.proc.0006