Digital Library

The optical characteristics of thin films can display remarkable sensitivity to the refractive index of the constituent material, making phase-change materials particularly interesting for sensing purposes. Among these materials, vanadium dioxide (VO₂) stands out for its exceptional performance. It undergoes significant shifts in refractive indices and electrical conductivity during its transition from insulator to metal, which occurs at approximately 70 °C, a temperature not far from room temperature. The versatility of VO₂ lies in its ability to undergo phase transition triggered by various stimuli including heat, light, and electric fields, enabling a broad range of sensor applications. One effective approach involves observing the interaction of light and infrared radiation with VO₂ films and analyzing the resulting alterations in amplitude and polarization states. These changes can be precisely measured using signal modulation and amplification techniques, facilitating the development of miniaturized sensors. Films as thin as 50 nanometers can be utilized in this setup. In this study, we outline and demonstrate methodologies employing VO₂ thin films to detect subtle fluctuations in temperature and electrical currents. The sensing mechanism capitalizes on the generation of heat through mechanical means, such as friction, or electrical heating via the Joule effect. The paper will discuss theoretical limits and provides proof of concept demonstrations.

https://doi.org/10.14332/svc24.proc.0045

The hydrogen market is growing rapidly. The industry is developing for technical solutions for hydrogen generation and hydrogen-based electricity generation for mobile and stationary applications, and universities and institutes are investigating solutions for the long term. Today’s challenge is to bridge the gap between current low to medium technology maturity level and market demand: how to be able to produce hydrogen on large scale and how to scale fuel cell production to high volumes? IHI Hauzer is working on this challenge for many years, developing low cost coatings to supply to the market either by machine solutions and coating services. Key components of electrolyzers and fuel cell stacks like bipolar plates, PTL sheets and CCM’s need high quality coatings to enable good catalyst performance, good electrical conductivity and good corrosion properties. For bipolar plates and PTL sheets, Hauzer has developed coatings based on PVD technology. In the presentation the actual state of the art will be addressed, including the current status of market introduction and our expected further roll-out within the next years. For PVD, the current main challenges related to machine and process solutions for high speed inline coating will also be addressed. We will further address the requests from the market especially the electrolyzer business and give an outlook about possible solutions to serve these demands.

https://doi.org/10.14332/svc24.proc.0044

Carbon-based electrochemical sensors for aqueous solutions are typically screen-printed on rigid and flexible substrates. However, most of those electrode materials are poorly suited for non-aqueous solvent electrochemistry due to their binder system. This limitation spurs interest in exploring alternative carbon-based electrode materials. While boron-doped diamond (BDD) electrodes are inert to such conditions, high processing temperatures and complex scalability make them cost prohibitive for low-cost disposable sensing applications. Addressing this, we investigate the viability of a nitrogen-incorporated tetrahedral amorphous carbon (ta-C:N) as an effective solution. Ta-C:N is a highly sp³-bonded carbon n-type semiconductor with electrochemical properties comparable to BDD such as low background current and noise, and good microstructural stability at positive detection potentials. Ta-C:N thin films are synthesized by physical vapor deposition (PVD). As a result, low processing temperature, commercially available, industrial-scale systems and processes are available for potential roll-to-roll production. Here, we have developed and fabricated a ta-C:N 3-in-1 style electrochemical sensor on a rigid silicon substrate. The electrode configuration included a ta-C:N based counter, working, and reference electrode. The amorphous carbon was directly deposited onto the substrate by laser controlled pulsed cathodic vacuum arc (Laser-Arc) and patterned by a standard liftoff photolithography process. While evaluating the same electrode material on flexible polyimide substrates, we observed cracking and delamination after initial electrochemical testing. As a result, further surface engineering was required to withstand such conditions. Hence, this study also investigates different substrate pretreatments and/or interlayers for ta-C:N on polyimide and their effect on the electrical and electrochemical performance of the functional ta-C:N top layer compared to ta-C:N on conductive silicon.

https://doi.org/10.14332/svc24.proc.0046

Developing precise Lead-Selenide (PbSe) gratings with narrow slots is essential for the advancement of mid-infrared (MIR) technologies used in spectroscopy, thermal imaging, and environmental sensing. A major hurdle in fabricating these components is the tendency for increased irregularities and reactive ion etching (RIE) delays in the etched profiles as the slot width becomes smaller. This talk identifies the accumulation of charge on non-conductive photoresist as the primary source of these irregularities. By applying a conductive copper layer, we can neutralize this charge, allowing for the successful etching of gratings with significantly enhanced profiles and slot widths reaching as low as 0.7 μm. This breakthrough not only boosts the sensitivity and resolution of MIR devices but also paves the way for novel applications in areas such as security and healthcare.

https://doi.org/10.14332/svc24.proc.0048

In-line coating systems are ideally suited for high volume production applications over a wide range of substrate sizes and geometries. Parts are fed in on one side of the coating plant, run through the various process chambers and are finally released to atmosphere at the other end of the coating system.
PVT has designed and developed different in-line coating systems that are ideally suited for Physical Vapor Deposition (PVD) coating of bipolar plates for fuel stacks and electrolyzers in high volume. In-line coating systems are characterized by the ability to perform each step of the coating process in its own dedicated vacuum chamber. Process chambers are isolated from each other by large area transfer valves.
Multi-layer film stacks are deposited in a highly productive process cycle. PVT will present its newest in-line system which is extremely productive and versatile using magnetron sputtering and HiPIMS.
PVT is offering coating service with this in-line system for development and pilot production applications. Properties of the different coatings deposited by HiPIMS and dual magnetron sputtering are presented such as ICR – values and corrosion data.

https://doi.org/10.14332/svc24.proc.0043

Bipolar pulsed sputter deposition provides a robust method for depositing insulating coatings like oxides and nitrides. For several years, both sine-wave and squarewave generators have been utilized for these processes. Different applications demand stringent and distinct coating requirements, and pulse mode provides an additional variable enabling a user to optimize film microstructure and thereby film properties. This presentation shows a comparative study of three types of bipolar pulsed modes: symmetric sinusoidal pulsing, symmetric square pulsing and the new asymmetric square pulsing mode called dynamic reverse pulsing. The three modes were tested on reactive sputter deposition of silicon nitride films in an industrial drum coater. The aim is to provide a comprehensive understanding of the different modes and their influence on the film properties in terms of deposition rate, heat load at the substrate, residual stress and optical properties. We show that the different pulse modes have inherent differences in plasma behavior and we outline their benefits.

https://doi.org/10.14332/svc24.proc.0024

Atomic Layer Deposition (ALD) is now a well-established process broadly used in the manufacture of leading-edge semiconductor chips. ALD is required for this application due to its high level of precision and ability for conformal deposition of pinhole-free coatings on complex surfaces. These same coating attributes are highly desirable in other applications, such as thin film encapsulation, on the large area substrates used in the display and photovoltaic industries. But to date, scaling of ALD processes to such large substrates, with sufficient throughput and at the low cost required for these applications, has been elusive. In this work, a novel Spatial Plasma Enabled ALD (S-PEALD) process is demonstrated that offers the economic scalability of ALD to these large area substrates. The use of a simple DC plasma source, enabled by the use of spatial processing, allows plasma generation over the multi-meter distances required for these substrate sizes. Meanwhile, a novel method for spatial precursor separation provides the means to utilize a simple, compact, and rapidly moving coating head for executing the ALD cycle. In combination with a mixed oxide barrier material, a process is demonstrated that provides a path to the in-line deposition of OLED-quality barrier coatings on multi-meter substrates, with a takt time of less than one minute.

https://doi.org/10.14332/svc24.proc.0022

processes. Ampres has developed a new generation of scalable closed drift gas ionizers. These sources provide an economical tool for the deposition of complex high quality multilayer thin film coatings. The gas ionizers provide very high ionization rates in a compact fully scalable design. They are used to supply ionized reactive gas for enhanced magnetron sputtering processes and for a unique hybrid PVD–PECVD process.
These sources are ideally suited to deliver ionized reactive gases like Oxygen, Nitrogen and Fluorine direct to the substrate surface to form metal oxide, metal nitride and other complex thin film coatings. They also can be used as standalone plasma sources for PECVD and plasma etching applications.

https://doi.org/10.14332/svc24.proc.0023

The Vera C. Rubin Observatory construction is poised to be completed, finishing the Integration phase and starting the Commissioning phase. The Coating Plant is delivering the coated main science mirrors to the project. The M2 mirror was coated with protected Silver in 2019 and the M1M3 mirror coated in 2024 with protected Silver as well, both coatings achieving the main project requirements. This paper describes the main project milestones in terms of construction, assembly and integration, the coating results on both mirrors. This paper also describes a characterization of the Coating Plant and its ancillary equipment, a characterization of the coating delivered by us, the coating tests that we made prior of the final coating recipe decision, and the final coating results over the main telescope mirrors, finishing with the future projects related to this Coating System.

https://doi.org/10.14332/svc24.proc.0025

Modern society runs on seamless mobile connectivity. Yet, the wide commercial adoption of low-emissivity (low-E) windows introduces significant problems in the transmission of mobile signals, which is further exacerbated by the global adoption of 5G networks, particularly mid to high-band 5G frequencies. This presentation introduces a production-line integrated and cost-competitive low-E manufacturing technology enabling mobile signal penetration of low-E windows while maintaining optical and thermal performance. Core technology leverages lithography and is fully compatible with the throughput of existing Low-E production lines. Final low-E products enable 5G transmission across low and high frequency bands while maintaining superior visual aesthetics with invisible pattern lines under any angle and any lighting conditions. Furthermore, the technology meets low-E’s durability criteria, including mechanical alcohol wiping durability and thermal tempering tests. Supported by NSF funding, this project aims to commercialize next-generation mobile signal penetrating Low-E products at scale and cost competitively for global adoption in architectural applications to enhance indoor connectivity in the 5G era.

https://doi.org/10.14332/svc24.proc.0021