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Rugate optical thin films have been studied for several decades, particularly for the application to laser eye protection filters (LEPF). The principles of rugates and Herpin equivalent layers are briefly reviewed. The combination of these concepts to overcome the bandpass limitations of shortwave pass filters is shown. The use of Alfred Thelen’s minus filters to make LEPF is discussed. The use of higher harmonic bands of quarter wave optical thickness (QWOT) stacks for LEPF is explained. The application of thickness ratios in layer pairs other than QWOTs is shown to lead to better alternatives for LEPF than rugates.

https://doi.org/10.14332/svc25.proc.0019

This research explores the mechanical properties of thin films designed as a platform for subsequent diamond-like carbon (DLC) deposition. Beyond its well-known tribological properties, DLC also serves as an effective antireflective (AR) coating in the infrared (IR) range, addressing the dual requirement of optical functionality and mechanical durability in IR substrates. The goal of this study is to investigate the impact of the binding layer (BL) thickness on adhesion and mechanical properties, highlighting an optimal thickness identified through systematic testing. Adhesion in such multilayer systems is critically influenced by how well the BL accommodates residual and interfacial stresses while bridging the mismatch in hardness and modulus between the substrate and the overlying layers. A BL that is too thin cannot effectively prevent stress concentration or crack propagation, whereas a BL that is too thick may accumulate stress and reduce load transfer efficiency. Accordingly, we investigated two film configurations deposited on silicon wafers using the magnetron sputtering technique. In one configuration, the BL, deposited directly on the substrate, was systematically varied in thickness, along with the AR layer, an amorphous silicon (a-Si) optical layer, which was deposited at a constant thickness of 1.12 μm on top. In the other configuration, the same BL thickness range was studied without the a-Si optical layer. Nanoindentation and scratch testing revealed that both hardness and critical load peaked at an intermediate BL thickness, and the maximum fracture load was found in the hardest films, emphasizing the balance between adhesion and fracture resistance at this optimized thickness. The constant thickness of the a-Si optical layer ensured that BL thickness was the only variable parameter in the study. These findings offer valuable insights into the optimization of AR coatings with integrated adhesion layers, which are crucial for creating robust platforms for DLC deposition in high-performance IR optical systems.

https://doi.org/10.14332/svc25.proc.0020

In this study, we introduce an alternative leak detection method based on remote plasma optical emission spectroscopy (RPOES). The technique exploits plasma-induced light emission to detect leaks in real time, enabling both detection and localisation using trace gases such as argon that are relatively inexpensive and readily available. Compared with mass-filter helium detectors, RPOES provides greater robustness, the ability to operate at higher pressures, and reduced maintenance demands. We outline the principles of RPOES, emphasise its advantages in detecting gases commonly linked to vacuum leaks (including water vapor and air), and assess its viability as a practical alternative to helium-based methods. Case studies are presented to demonstrate its effectiveness in identifying leaks across a range of coating applications, with ultimate aim to improved process stability, enhanced coating quality, and lower operational costs.

https://doi.org/10.14332/svc25.proc.0038

Sputtered oxide thin films hold enormous potential in a wide range of both mature and growing new applications, from energy-efficient glazing and advanced displays to next-generation energy generation and storage solutions. Their unique ability of tunable morphology, providing a desired combination of optical performance and electrical properties, makes them a key component for emerging technologies. Among the various deposition methods, sputtering of ceramic targets has proven to be a versatile and efficient technique for producing high-quality oxide thin films with tailored properties. This study investigates the role of recently developed ceramic target materials in achieving high deposition rates, enhanced material utilization and improved film properties compared to traditional sputtering of metallic targets. Ceramic targets offer superior thin film stoichiometric control, ensuring precise composition of the deposited thin films. Furthermore, combining these targets with advanced sputtering and inline metrology equipment provide enhanced process stability, allowing to maintain film uniformity and composition in large area and industrial production environments. The introduction of easy-to-use process control tools as part of an advanced system software platform enables achieving and sustaining the desired performance of these thin films. Our presented findings will highlight the immense potential of ceramic targets in advancing technologies for use in electrochromic devices, photovoltaic systems, and thin-film batteries. By enabling high-performance solutions, ceramic target-based sputtering addresses the growing demand for functional coatings in large-area applications. These innovations unlock new possibilities for scalable and sustainable technologies, making sputtered oxide thin films from ceramic targets and in combination with advanced magnetron and process capabilities a cornerstone for future advancements in materials science and engineering.

https://doi.org/10.14332/svc25.proc.0016

TiO₂ films were sputtered by a bipolar pulsed-DC process from a pair of sub-stoichiometric TiO_x targets. By utilizing process gas analysis, we find that the largest impact on a reliable batch process lies in both the control of the adsorbed humidity and inlet of oxygen sputtering gas. After establishing this understanding, we show that high quality films can be deposited for any pulsing frequency between 0.5 kHz and 50 kHz with the lower frequencies having a beneficial impact on refractive index, the substrate temperature, and less energy losses at the sputtering power supply.

https://doi.org/10.14332/svc25.proc.0041

This study explores the synthesis and characterization of Titanium Aluminum Carbon Nitride (TiAlCN) coatings, a pioneering advancement in surface engineering. Using reactive High Power Impulse Magnetron Sputtering (HiPIMS), we deposited TiAlCN coatings with varying carbon content (1.3 - 58.1 at.%) by modulating the acetylene flow rate. X-ray diffraction analysis revealed a carbon solubility limit of 17 at.% in the TiAlN structure, beyond which TiAl(CN) nanocrystals and an amorphous carbon phase emerged. This structural evolution significantly impacted the coatings' properties. Notably, increasing carbon content noticeably reduced the coefficient of friction from 0.62 (TiAlN) to 0.22 (42 at.% C), enhancing tribological performance. However, high carbon concentrations impeded aluminum diffusion, hindering the formation of a protective Al₂O₃ layer and consequently diminishing corrosion resistance. Additionally, the presence of amorphous carbon between grains at elevated carbon levels led to a reduction in the coatings' mechanical properties.

https://doi.org/10.14332/svc25.proc.0025

Achieving high-quality ultrathin silver coatings is challenging due to silver's tendency to form clusters during deposition, resulting in inhomogeneous layers with pinholes and rough surfaces. These issues limit the overall quality and the minimum achievable thickness of usable silver layers. A literature review revealed that recent studies have reported improved quality of ultrathin silver layers by incorporating small amounts of dopant materials, which help silver atoms distribute more evenly across the surface. Various dopant materials and deposition processes have been explored in these studies. In our research, we utilized copper as the dopant material and employed Thermal Evaporation Physical Vapor Deposition (PVD) as the deposition process. This approach resulted in significantly improved homogeneity and smoother surfaces with fewer geometric anomalies. The spectral transmittance of the doped silver layers was closer to the calculated ideal, and light scattering was reduced. Consequently, the minimum usable layer thickness was successfully decreased to approximately 11 nm while maintaining high quality. Less thin layers, in the range 12 nm – 25 nm showed improved performance. In addition, the resulting performance was less sensitive to deposition rate during the coating process.

https://doi.org/10.14332/svc25.proc.0029

Multi-component ceramic coatings such as TiN, CrN, TiAlN, TiCrN, TiCrSiN and Hard carbon coatings (HCC) were used in wide range of industrial applications, as these have excellent mechanical, chemical and biological properties. These coatings were synthesized by the vapour-phase method from an arc ion plating process. PVD (Physical Vapor Deposition) coating technologies were commonly used in carrying out ceramic coatings, where the coating materials are vaporized from the source and then transported in the form of a vapour through a vacuum or plasma environment to the substrates.

https://doi.org/10.14332/svc25.proc.0022

The advent of Zoom and Team Meetings and other face-time communications has made the annoyance of reflections from uncoated eyeglasses more apparent. Even the residual reflections from some of the current commercially available antireflection (AR) coatings can be distracting. The goal of this work is to find the most practical recommended AR coating design for the next generation of eyeglass coatings which will effectively eliminate these annoying reflections which are currently seen when in a Zoom or Teams meeting with those who do not have sufficiently well-coated glasses. The evolution of the designs from many layers to the recommended four layers will be presented.

https://doi.org/10.14332/svc25.proc.0017

Complex vacuum coating systems for the production of multilayer coatings using PVD offer a variety of parameters for process optimization. An important factor for achieving the best productivity is the maximum deposition rate of the roll-to-roll PVD process. The wrinkling of the substrates due to stress during the coating process has a limiting effect. Different polymers require individual parameterization of the system.

The lecture presents the possibilities of system technology to increase productivity. Based on several examples, results for the best parameterization of the system for optimized coating deposition will be discussed.

https://doi.org/10.14332/svc25.proc.0027