X-CONDUCT Kohlenstoffbeschichtung für verbesserte Leitfähigkeit und Korrosionsbeständigkeit

Metallische Bipolarplatten für PEM-Brennstoffzellen und PEM-Elektrolyseure benötigen funktionale Beschichtungen für Leitfähigkeit, Korrosionsschutz sowie als Barriere gegen Ionenaustrag und Wasserstoffversprödung. Kohlenstoffbeschichtungen haben sich als primäre Lösung etabliert, da sie all diese Funktionen zu niedrigen Kosten erfüllen. Dennoch stoßen sie bei hohen Korrosionsspannungsspitzen während des Kaltstarts von Brennstoffzellensystemen und den damit verbundenen Belastungen für die Lebensdauer deutlich an ihre Grenzen.

Deshalb hat VON ARDENNE die neue Kohlenstoffbeschichtung X-CONDUCT entwickelt, die selbst unter anspruchsvollsten Bedingungen unvergleichliche Leitfähigkeit und Korrosionsbeständigkeit bietet. Der deutliche Leistungsgewinn wurde durch den Einsatz der neuesten PVD-Technologie des Unternehmens – der High Current Laser Arc (HCLA) Verdampfung – erreicht.
X-CONDUCT übertrifft nicht nur andere Kohlenstoffbeschichtungen in puncto Leistung, sondern setzt auch neue Maßstäbe bei den Gesamtbetriebskosten dank der erfolgreichen Skalierung der HCLA-Technologie und des energieeffizienteren Kohlenstoffabscheidungsprozesses.

VICA900: Die weltweit erste PVD-Inline-Beschichtungsanlage mit HCLA-Technologie

VON ARDENNE hat nicht nur den HCLA-Prozess skaliert, sondern auch eine völlig neue Anlagenplattform – die VICA900 – entwickelt. Diese PVD-Anlage ist eine echte Innovation, da sie das Prinzip der kontinuierlichen Inline-Beschichtung erstmalig mit der HCLA-Technologie kombiniert. Diese bahnbrechende Innovation unterstreicht die branchenführende Expertise des Unternehmens in der Skalierung neuer Technologien sowie in der Konzeption, Konstruktion und der Fertigung von erstklassigen PVD-Inline-Beschichtungsanlagen.

Mit dem Fokus auf optimierte Gesamtbetriebskosten ermöglicht die VICA900-Plattform die beidseitige Beschichtung in vertikaler Anordnung. Durch die Integration von Vorbehandlungsprozessen wie Plasmaätzen sowie Magnetron-Sputtern und HCLA-Verdampfung bietet die Anlagenplattform die Flexibilität und Skalierbarkeit, für die VON ARDENNE bekannt ist.

In der Basiskonfiguration, der VICA900 Mid Volume, zielt das System auf eine Jahresproduktion von 4,6 bis 6,4 Millionen Bipolarplatten ab und konzentriert sich auf Beschichtungen für PEM-Brennstoffzellenanwendungen. Es kann durch zusätzliche PVD-Prozessquellen erweitert werden, um weitere Anwendungen wie beispielsweise doppelseitige Edelmetall-Beschichtung für PEM-Elektrolyseur-Komponenten zu ermöglichen. Durch eine weitere Aufrüstung der Maschinenkonfiguration kann der Durchsatz deutlich gesteigert werden, sodass in der VICA900 High Volume Ausführung bis zu 10 Millionen Bipolarplatten pro Jahr beschichtet werden können.

VON ARDENNE und die GERMAN FUEL CELL COOPERATION auf der H2 & FC Expo 2026 – Stand und Kontakt

DATUM: 17. – 19. März 2026

STAND: W11/58

WEB:
www.vonardenne.com | www.fuel-cell-cooperation.com | www.wsew.jp

X-CONDUCT carbon coating for enhanced conductivity and corrosion resistance

Metallic bipolar plates for PEM fuel cells and PEM electrolyzers require functional coatings for conductivity, corrosion protection, and as a barrier against ion elution and hydrogen embrittlement. Enabling all these functions at low cost, carbon coatings have established themselves as a primary solution. However, they clearly face limitations when exposed to high corrosion voltage peaks during cold start of fuel cell systems and the related impact on lifetime.

This is why VON ARDENNE has developed the new carbon coating, X-CONDUCT, for unrivaled conductivity and corrosion resistance even under harsh conditions. The significant boost in performance was achieved by using the company’s most recent PVD technology – High Current Laser Arc (HCLA) evaporation.

X-CONDUCT not only outperforms other carbon coatings in terms of performance but also sets new standards regarding the total cost of ownership due to the successfully achieved scale-up of the HCLA technology and the more energy-efficient carbon deposition process.

VICA900: The world’s first PVD inline coating machine using HCLA

VON ARDENNE has not only scaled up the HCLA process but also developed a completely new equipment platform – the VICA900. This PVD (physical vapor deposition) machine is a true innovation as it combines the principle of continuous inline coating with HCLA technology.  This groundbreaking innovation highlights VON ARDENNE’s industry-leading expertise in scaling new technologies and in designing and manufacturing best-in-class PVD inline coating systems.

With a focus on optimized total cost of ownership, the VICA900 platform supports double-sided coating in a vertical configuration. By integrating pre-treatment such as plasma etching processes, magnetron sputtering and HCLA evaporation, the system offers the flexibility and scalability that VON ARDENNE is renowned for.

In its base configuration, VICA900 Mid Volume, the system targets an annual output of 4.6 to 6.4 million bipolar plates and focuses on coatings for PEM fuel cell applications. It can be extended with additional PVD process sources to accommodate further applications, such as double-sided precious metal coating for PEM electrolyzer components. By further upgrading the machine configuration, the throughput can be significantly increased, achieving up to 10 million coated bipolar plates per year in the VICA900 High Volume setup.

VON ARDENNE and the GERMAN FUEL CELL COOPERATION at the H2 & FC EXPO 2026 – Booth and Contact

DATE: 17^th – 19^th March 2026

BOOTH: W11/58

WEB:

www.vonardenne.com | www.fuel-cell-cooperation.com | www.wsew.jp

This industry-focused project brings together leading partners across the entire value chain: Whitecell Eisenhuth develops and evaluates new materials, VON ARDENNE contributes its expertise in coating, the ISFH develops alternative PVD coatings and conducts ex-situ and short-term in-situ testing, while the IfES carries out long-term experiments, modeling, and techno-economic analysis. Finally, iGas-Energy ensures the transfer of the developed materials into commercial applications. The project is supported by Germany’s Federal Ministry for Economic Affairs and Energy.

With this strong industry and research consortium, TiSPA is aiming to make an important contribution to making PEM water electrolysis more cost-efficient and thus more competitive for large-scale deployment in the hydrogen economy.

The Project Partners

Institute of Electrical Power Systems (IfES)

The Institute of Electrical Power Systems (IfES) – Electric Energy Storage Systems Section at Leibniz University Hannover – conducts research and development on technologies for the efficient conversion, storage, and utilization of electrical energy. A particular focus lies on PEM water electrolysis, a key technology for sustainable hydrogen production. The IfES investigates fundamental physicochemical processes such as product permeation, gas purity, multiphase mass transport, and current density distribution in spatially distributed cells. The goal is to gain a deeper understanding of the dynamic operating behavior of electrolyzers and to develop innovative concepts for their stable and efficient integration into future energy systems. Combining model-based system analysis, numerical simulation, and experimental validation, the IfES is among the leading research institutions in the field of electrochemical energy conversion.

iGas energy

iGas energy GmbH, headquartered in Stolberg, North Rhine-Westphalia, specializes in developing and manufacturing systems that recover and repurpose resources once considered lost. At the heart of its innovation lies deep expertise in gas technology – particularly in handling hydrogen.

In the field of water electrolysis, iGas has developed a PEM electrolyzer stack known as ELZA, distributed through the Bosch Group. The company has also developed the Green Electrolyzer, a modular, container-based PEM electrolysis system marketed by its partner, Fest GmbH. Beyond product development, iGas is actively involved in research projects focused on PEM electrolysis and electrochemical processes in general – continuously pushing the boundaries of sustainable energy solutions.

Institute for Solar Energy Research in Hamelin (ISFH)

ISFH develops innovative technologies for a sustainable energy supply and stands for industry-oriented research. With around 165 employees, it conducts research in two departments on efficient solutions for the use of solar energy and renewable energy supply for buildings and neighborhoods. The Photovoltaics department focuses on the development of new industry-oriented solar cell technologies, highly efficient industrializable photovoltaic modules and investigates the integration of PV in innovative systems. The Solar Systems Technology department develops solutions for the integration of solar energy, heat pumps and hydrogen into our future sustainable energy system. ISFH is a member of the Research Association for Renewable Energies (FVEE) and the Zuse Association as well as an affiliated institute of Leibniz Universität Hannover.

Whitecell Eisenhuth

Whitecell Eisenhuth, based in Osterode am Harz, has established itself as a respected manufacturer of bipolar plates and gaskets and offers tailor-made solutions for fuel cell manufacturers who are ready to launch their products on the market. In the context of developments in the field of electrolysis, Whitecell Eisenhuth has developed composite plates, among other things, and currently produces them in small series with its 65 employees. The experience and existing technology gained from these activities can also benefit the project applied for here.

Das industriegeführte Projekt bündelt die Kompetenzen führender Partner entlang der gesamten Wertschöpfungskette: Whitecell Eisenhuth entwickelt und untersucht neue Materialien und -Kombinationen, VON ARDENNE bringt seine Expertise in der Vakuum- bzw. PVD-Beschichtung ein, das ISFH entwickelt alternative PVD Beschichtungen und prüft die Materialien in ex-situ- und Kurzzeit-in-situ-Tests, während das IfES Langzeitversuche, Modellierungen und eine technoökonomische Analyse durchführt. Schließlich sorgt iGas-Energy für die Überführung der entwickelten Materialien in die kommerzielle Anwendung. Das Projekt wird durch das Bundesministerium für Wirtschaft und Energie gefördert.

Mit diesem starken Industrie- und Forschungsverbund hat TiSPA das Ziel einen entscheidenden Beitrag zu leisten, die PEM-Wasserelektrolyse kosteneffizienter und damit wettbewerbsfähiger für den breiten Einsatz in der Wasserstoffwirtschaft zu machen.

Die Projektpartner

Institut für Elektrische Energiesysteme (IfES)

Das Institut für Elektrische Energiesysteme (IfES) – Fachgebiet Elektrische Energiespeichersysteme der Leibniz Universität Hannover – erforscht und entwickelt Technologien zur effizienten Wandlung, Speicherung und Nutzung elektrischer Energie. Ein besonderer Schwerpunkt liegt auf der PEM-Wasserelektrolyse, einem zentralen Verfahren zur nachhaltigen Wasserstofferzeugung. Das IfES untersucht dabei grundlegende physikalisch-chemische Prozesse wie Produkt-Permeation, Gasreinheit, Mehrphasen-Stofftransport und Stromdichteverteilungen in ortsausgedehnten Zellen. Ziel ist es, das dynamische Betriebsverhalten von Elektrolyseuren besser zu verstehen und innovative Konzepte für eine stabile und effiziente Integration in zukünftige Energiesysteme zu entwickeln. Mit seiner Kombination aus modellbasierter Systemanalyse, numerischer Simulation und experimenteller Validierung zählt das IfES zu den führenden Forschungseinrichtungen im Bereich elektrochemischer Energiewandlung.

iGas energy

Die iGas energy GmbH, mit Sitz in Stolberg, Nordrhein-Westfalen, entwickelt und produziert Anlagen, die vermeintlich verloren gegangene Ressourcen wieder effizient nutzbar machen. Dreh- und Angelpunkt ist dabei das profunde Know-how aus der Gastechnik und insbesondere die Erfahrungen im Umgang mit Wasserstoff. Im Bereich der Wasserelektrolyse hat iGas bereits einen PEM-Elektrolysestack unter dem Produktnamen ELZA entwickelt, der über die Bosch Group vertrieben wird, sowie die modulare, containerbasierte PEM-Elektrolyseanlage, den Green Electrolyzer, welcher von dem Partner der Fest GmbH vermarktet wird. Darüber hinaus engagiert sich die iGas fortlaufend in Forschungsprojekten zur PEM-Elektrolyse sowie zu anderen elektrochemischen Prozessen.

Institut für Solarenergieforschung in Hameln (ISFH)

Das ISFH entwickelt innovative Technologien für eine nachhaltige Energieversorgung und steht für eine industrienahe Forschung. Mit rund 165 Mitarbeiterinnen und Mitarbeitern forscht es in zwei Abteilungen an effizienten Lösungen für die Nutzung von Solarenergie und regenerativer Energieversorgung von Gebäuden und Quartieren. Die Abteilung Photovoltaik konzentriert sich auf die Entwicklung von neuen industrienahen Solarzellentechnologien, hocheffizienten industrialisierbaren Photovoltaikmodulen und forscht an der Integration von PV in innovativen Systemen. Die Abteilung Solare Systemtechnik entwickelt Lösungen für die Integration von Solarenergie, Wärmepumpen und Wasserstoff in unser zukünftiges nachhaltiges Energiesystem. Das ISFH ist Mitglied im Forschungsverbund Erneuerbare Energien (FVEE) und der Zuse-Gemeinschaft sowie An-Institut der Leibniz Universität Hannover.

Whitecell Eisenhuth

Whitecell Eisenhuth, mit Sitz in Osterode am Harz, hat sich inzwischen als angesehener Hersteller von Bipolarplatten und Dichtungen etabliert und bietet maßgeschneiderte Lösungen für Hersteller von Brennstoffzellen, die ihre Produkte bereits auf dem Markt einführen möchten. Im Kontext der Entwicklung im Bereich der Elektrolyse hat Whitecell Eisenhuth unter anderem Composite-Platten entwickelt und produziert mit seinen 65 Mitarbeitenden diese derzeit in kleinen Serien. Die Erfahrungen und vorhandene Technologie aus diesen Aktivitäten können auch dem hier beantragten Projekt zugutekommen.

“As the semiconductor industry pushes the boundaries of performance and miniaturization, VON ARDENNE is stepping into the US market with next-generation tool platforms, co-developed materials solutions, and custom refurbishment and upgrade services,” said Guido Ueberreiter, vice president of semiconductor strategy at VON ARDENNE. “Our approach enables semiconductor manufacturers to overcome complex deposition and vacuum challenges, particularly where legacy tools fall short or off-the-shelf solutions can’t meet emerging needs. Our OPTA X300 platform is purpose-built for high precision double-sided deposition to support the most demanding multilayer applications.”

Flagship Showcase: OPTA X300

At SEMICON West, VON ARDENNE will feature its OPTA X300 rotary disk coating system, the company’s flagship platform for sub-nanometer precision deposition on demanding substrates. Purpose-built for electrical and optical layers for memory, photonics and sensor devices, the OTPA X300 offers flexibility to support customers from R&D through high-volume manufacturing.

The OPTA X300 platform will be installed at VON ARDENNE’s new ISO 5 cleanroom in Dresden, which serves as a cornerstone of its Technology and Applications Center. This facility enables customers to test, sample and co-develop deposition processes with access to industry-leading engineering and materials science expertise.

Cleanroom Capabilities

The new cleanroom features 200 m² of ISO 5 (Class 100) assembly and test bays with airborne molecular contamination control (AMC) as well as 400 m² of ISO 7 cleanroom manufacturing space in Dresden. The cleanroom is designed for semiconductor, optical and space applications and is extreme ultraviolet (EUV)-ready. The OPTA X300 will be available for customer demos and co-development projects starting mid-2026.

“US fabs need more than tool suppliers, they need engineering partners who understand both the equipment and the materials science behind next-generation devices,” said Michael Schneider, vice president of semiconductor and precision optics at VON ARDENNE. “We’re bringing that integrated expertise to the US market—helping customers unlock new levels of performance, customization and yield.”

Also being showcased at the VON ARDENNE SEMICON West booth are its HISS600, designed to deliver superior uniformity and high throughput for panel-level packaging, and VISS, a modular vertical coating platform ideal for scaling from lab to production for substrates up to 600 mm.

For more information, visit https://vonardenne.us/industries-applications/semiconductors/. To schedule a demo or speak with a VON ARDENNE representative, contact radach.daniel@vonardenne.com.

In diesem Artikel konzentrieren wir uns auf das fortschrittliche Design der VON ARDENNE Linearverdampfer und beschreiben deren einzigartigen Merkmale. Eine schematische Darstellung eines Linearverdampfers ist in Abbildung 2 zu sehen, um die Hauptbestandteile zu erklären. 

Das Targetmaterial wird als Pulver in einen Tiegel gefüllt. Das große Tiegelvolumen der linearen Verdampfer gewährleistet lange Produktionszyklen. Darüber hinaus garantiert das Design des linearen Verdampfers eine große Verdampfungsoberfläche, da das Heizsystem eine große Fläche überdeckt.

Der Tiegel wird homogen beheizt, damit beginnt das Material zu verdampfen, wenn die materialspezifische Schmelztemperatur überschritten wird. Oder bei sublimierenden Materialien wird der Dampf aus der festen Phase freigesetzt. Die Menge des freigesetzten Materialdampfs steigt mit der Verdampfungsoberfläche und mit zunehmender Temperatur gemäß der „Clausius-Clapeyron-Gleichung“.

Der Tiegel ist gasdicht mit dem ebenfalls homogen beheizten Verteilungssystem verbunden. Durch die Wahl eines geeigneten Rohrdurchmessers und Düsensystems, das den Ausfluss begrenzt, kann der Materialdampf über lange Strecken mit vernachlässigbaren Druckänderungen homogen verteilt werden.

Während ein kaltes Substrat – entweder Wafer oder Glas – kontinuierlich unter dem Materialfluss des Düsensystems transportiert wird, kondensieren die ankommenden Partikel darauf. Die Partikel bilden eine gleichmäßige Beschichtung, deren Fläche durch die Breite des Düsensystems definiert und theoretisch beliebig lang ist.

Für die präzise und reproduzierbare Kontrolle der resultierenden Schichtdicke sorgt ein Quarzkristallmonitor (QCM) innerhalb des linearen Verdampfungssystems. Der QCM misst die Abscheiderate des beschichteten Materials sehr präzise. Er dient als Referenzsignal für eine reproduzierbare und stabile Steuerung durch Anpassung der Leistung oder Temperatur.

Daher unterscheiden wir zwischen linearen Verdampferquellen für niedrige, mittlere und hohe Temperaturbereiche. Alle Systeme gewährleisten ein schnelles und zuverlässiges PID-gesteuertes Aufheizen und Abkühlen mit geringem Überschwingen, um temperaturempfindliche Materialien vor thermischem Stress zu schützen.

Darüber hinaus können industrielle Kampagnenzeiten erreicht werden durch:

• Spezielles Design des Ratenmonitors für Langzeitmessungen
• Große und anpassbare Tiegelvolumen ermöglichen ausreichende Materiallagerung (temperaturempfindliche Materialien)
• Optimiertes mechanisches Design für weitere wartungsbezogene Operationen wie den Austausch von Abschirmungen

Klicken Sie hier, um mehr zu erfahren oder Kontakt aufzunehmen.

In this article, we will focus on the advanced design of VON ARDENNE linear evaporators and describe their unique features. A schematic design of a linear evaporator is shown above to explain the main consisting parts. (Figure 2)

The target material is filled as a powder in a crucible. The large crucible volume of the linear evaporators ensures long production cycles. Furthermore, the linear evaporator design guarantees a large evaporation surface as a large area is exposed to the heating system.

Since the crucible is heated homogeneously, the material will start to evaporate when the material-specific melting temperature is exceeded. Or, for subliming materials, the vapor is emitted from the solid phase. The amount of material vapor that is released increases with the evaporation surface area and with increasing temperature following the “Clausius-Clapeyron Equation”.

The crucible is gas-tightly connected to the likewise homogeneously heated distribution system.  By a suitable choice of tube diameter and nozzle system limiting the outflow, the material vapor can be distributed homogeneously over long distances with negligible pressure changes.

As a cold substrate is transported continuously under the material flow of the nozzle system, the arriving particles condensate on the substrates, which are either wafers or glass. The particles form a uniform coating on an area defined by the width of the nozzle system and, theoretically, an undefined length.

The precise and reproducible control of the resulting film thickness is realized by a Quartz Crystal Monitor (QCM) within the linear evaporation system. The QCM sensitively measures the deposition rate of the coated material. It serves as reference signal for reproducible and stable control by either power or temperature adaption.

Thus, we distinguish between low, medium and high-temperature-range linear evaporator sources. All systems ensure a fast and reliable PID-controlled heating up and cooling down with low overshooting to protect temperature sensitive materials from thermal stress.

Moreover, industrial campaign times can be achieved by

• Special design of rate monitor for long time measurement
• Large and adaptable crucible volumes enable sufficient material storage (temperature sensitive materials)
• Optimized mechanical design for other maintenance related operations such as replacement of shieldings

Click here to learn more or to get in touch.

Similarly, its discoverers would certainly never have dreamed how its targeted application would change everyday life to such an extent. Entire industries, such as electronics and microelectronics, bear his name. Neither computers nor modern communication or the internet would be conceivable without the targeted use of the properties of the electron.

But the electron is also very useful as a tool. This is particularly true for accelerated electrons that are focused into a beam. Electrons scan surfaces and provide optical information in the nanometer range, which has advanced science enormously over the last 80 years. In the past, electron beams were also used to generate images. Beyond that, electron beams are also used to bond different metals together, to harden surfaces and to modify plastics.

Electron beams can also be used to efficiently melt and clean refractory metals such as titanium, tungsten and tantalum. Or metals and ceramics can be deposited as functional layers on a wide variety of substrates by vaporization. This article will take a closer look at the latter applications in particular – in conjunction with the work of Manfred von Ardenne in Dresden.

Even though Marcello von Pirani had already patented the melting of refractory metals (in this case tantalum) using focused cathode rays in 1905, these findings had no useful effect at the time. This was due to the fact that neither effective high-vacuum pumps nor high-performance electron beam systems were available for industrial use at the time.

This required extensive developments in electron optics to shape the electron beam in the 1920s and 1930s. These were driven forward by the development of transmission electron microscopy by Ernst Ruska, Max Knoll and Manfred von Ardenne. At the same time, the applications of X-rays and the discovery of cosmic rays and the associated desire for experiments with high-energy radiation also awakened the desire for high-energy energy sources. In 1929, van de Graff achieved acceleration voltages of 1.5 MeV with his electrostatic band generator named after him. Manfred von Ardenne also used a generator of this type for experiments on neutrons in his former laboratory for electron physics in Berlin-Lichterfelde.

The limiting element in thermal emission was still the space charge in front of the cathode, which prevented emission currents above 1 mA. It was not until 1939 that John Pierce – in conjunction with the 3-electron system described by Rogowski in 1926 – showed a way to influence the field geometry by means of conical electrode geometries in such a way that significant electron emission was possible even with a large space charge.

The development of electron beam technology at VON ARDENNE

At the end of the Second World War, all the tools needed to start electron beam metallurgy were known. But it was not until 20 years later that industrial solutions for electron beam melting, evaporation and welding began to establish themselves.

In 1950, electron beam welding was first discovered more or less by chance in the electron microscope laboratory at Zeiss. K.H. Steigerwald then described the drilling of small holes and metalworking as possible applications of the electron beam. Already in 1938, Manfred von Ardenne had described this in a patent, together with von Borris and Ruska. He assumed that micromachining should be possible using a beam of charged particles.

In the 1950s, the focus on the development of space travel and nuclear research led to significant progress in this field. High-purity metals were needed for this, which required melting processes under extreme vacuum conditions. Arc and induction furnaces reached their limits. During this time, the first powerful electron beam guns were developed, which initially resembled electron microscopes.

However, the first axial EB guns still suffered from various problems. For example, the deposition of the vapor produced during melting quickly led to short circuits on the insulators. A decisive improvement was achieved here when it was realized that the beam diameter could be reduced to such an extent that the outlet opening could be used as a pressure stage to protect the insulators from the metal vapor.

Today’s high-performance electron emitters have several of these water-cooled pressure stages. In conjunction with separate evacuation systems, they protect the beam generation chamber on the vacuum side as far as possible from the harsh conditions in the melting or evaporation area.

A further increase in reliability and performance was achieved by using indirectly heated tungsten emitters. The actual large-area cathode is heated by the electron bombardment from a filamentary tungsten emitter on the back. This leads to an easily controllable and stable emission temperature.

From the very beginning, the space charge in front of the cathode was used as an emission-limiting factor. This ensured the necessary stability of the beam power and beam quality against fluctuations in the emission temperature or ageing of the cathodes.

First generation of electron beam guns for melting: powerful but bulky

On this basis, the first pilot-scale electron beam multi-chamber furnace with a beam power of 45 kW for melting steel was developed at the Manfred von Ardenne Research Institute (IvA) back in 1959. The strong demand from the metallurgical industry led to the development of much more powerful electron beam guns. Thus, by the mid-1960s, electron beam guns with a beam power of 1200 kW were already being produced at the IvA for metallurgical purposes.

Electron beam guns of this first generation still had a rather bulky design due to their high-voltage potential, directly water-cooled cathode systems and the required insulators. This was necessary because the thermal stability of the cathode system is of great importance for the beam quality and the heat had to be dissipated in this way, particularly in the case of the high-power guns of 1.2 MW.

In addition, at that time only oil diffusion pumps were available for the required high vacuum generation, which could be mounted via angled pipe sections. In conjunction with the dominant design of the isolators, these first-generation electron beam guns were also affectionately known as Christmas angels.

Improvements and further development: the second generation of electron beam guns

Despite the disadvantages, these guns used for melting refractory metals and for evaporating aluminum were very robust with their power classes between 60 kW and 1200 kW. Some of them are still in use today.

The increase in the range of applications, but also requirements for different installation positions and simplification of maintenance led to the development of the 2^nd generation of electron beam guns with several fundamental changes described below.

By changing the electrical potentials in the cathode heating system, the heating power could be reduced to a third. As a result, water cooling was no longer necessary and the cathode system, which had been drastically reduced in size and weight, could now disappear into the gun head, which was at ground potential.

Another important innovation concerned the power control. While the first-generation guns were still controlled by changing the accelerating voltage, the position of the anode could now be shifted by means of an actuator and thus also the beam current due to the variable distance between the cathode and anode.

As a result, both the accelerating voltage and the cathode temperature could be kept constant with this solution, known as a Vario Anode. It also reduced the influence of the power control on the electron-optical parameters. With this measure, the high-voltage insulation could be moved to the interior and the outer shell of the gun was completely at ground potential. This was a significant step forward in terms of safety and accessibility.

A further significant increase in reliability and operational safety was achieved by using a magnetically gas-focused electron beam. By measuring the temperature in the flow resistance, it was now possible to optimize and stabilize the beam focusing in the area of the flow resistances.

Recent developments

The development of the current, even slimmer-looking generation took place at the beginning of the 1990s. Extensive experience from the numerous 2^nd generation electron beam guns used in industry was taken into account. A fundamental innovation concerns the beam generation.

With the patented principle of the Vario Cathode, the electron beam power is now adjusted by changing the distance between the cathode and a fixed anode. This was made possible by moving the high-voltage insulator completely into the vacuum and thus significantly reducing the size.

Due to the principle of the Vario Cathode, the acceleration voltage and electron-optical geometry remain the same over the entire power range. This results in a much more constant and finely focusable beam quality over the entire power range, as the lens currents no longer have to be adapted to the beam power to the extent originally required. As a result, stable and reproducible beam operation across the entire power range was possible for the first time, which is very important for various applications.

A new cathode system design has also been introduced with the movement device for the cathode at high voltage potential. In conjunction with the cathode arrangement, which operates in space-charge mode, the design has been simplified to such an extent that the plugged-in cathode assembly can be easily replaced during maintenance by means of a quick-change system and no further adjustment of the cathode position is required. This design has been continuously optimized in recent years, resulting in a tried-and-tested industrial solution with a very long service life depending on the process.

In the last 10-15 years, the focus in the further development of the electron beam system has increasingly shifted towards components for high-voltage generation and beam guidance. In particular, the development of powerful medium-frequency power supplies with fast-switching transistors has led to significant progress in the suppression of high-voltage flashovers. The use of new materials in the beam deflection system and new concepts for the beam guidance software and control hardware also made it possible to increase the deflection frequencies even at large deflection angles. This also gave the operator many simple options for influencing the beam distribution.

Both the flashover cut-off and the increase in deflection frequency play a decisive role in current applications of electron beam technologies. For example, highly productive solutions for the evaporation of silicon oxide for barrier layers on transparent packaging films have been developed for coating applications, which are intended to replace the aluminum-based barrier layers that have mainly been used to date and are difficult to recycle. Due to the material, the evaporation of the silicon oxide takes place sublimating, i.e. without prior melting of the material. Short-term jet interruptions or inhomogeneities in the solid evaporation material therefore lead to a faster interruption of evaporation than in the thermally slower reacting molten state.

At the same time, the film to be coated is transported at speeds of up to 20 m/s. This means that if the electron beam is exposed for one millisecond, for example, the effect can extend to a strip length of up to two centimeters. On the generator side, the exposure time can now be limited to less than 300 µs. There are similarly high requirements for current coating applications in the battery sector, where a metallized plastic film is to replace metallic electrodes in lithium-ion batteries in the future.

High demands on precision, stability and repeatability also play a role in other applications. Here, the electron beam is used as an energy source to provide extremely high energy densities for material tests, as can occur when plasmas come into contact with the walls of particle accelerators. In order to be able to evaluate these energy densities, the electron beam must be very precisely adjustable in terms of beam diameter, energy and pulse duration. In the 60 years since the start of industrial use, all these requirements have led to a system of interlinked, tried and tested electron beam components as a toolbox for a wide range of applications.

More than ten years ago, VON ARDENNE took part in the transformation from point sources in batch systems to linear evaporators in continuously running inline coating systems. This happened especially in the OLED and display industry to achieve cost effective depositions on large areas.

Today, perovskite-based approaches are at the forefront of next-generation photovoltaics. We have adapted and improved our linear evaporators so that they work stably and reliably in this new field of application.

The advantages of vapor phase concepts compared to the solution-based processing of perovskite materials are being discussed in depth within the research community¹.

Challenges for large-scale perovskite PV inline manufacturing equipment:

• A coating width of more than 1.000 mm up to 3.000 mm
• A campaign length of at least 10 days
• Industrial-scale dynamic deposition rates to achieve high production throughput
• Conformal deposition on microtextured or textured pyramidal structures for Si-based bottom cells

The technological implementation of the evaporation process can be carried out using either point sources or linear sources. We argue that a point source as a part of a point source arrangement will be geometrically limited in volume, which may limit production time or will need a separate material supply for each point source to extend campaign times.

Beyond that, for point sources, the electrical supplies have to be multiplied by their number and an expensive rate monitor needs to be adapted for each point source in order to ensure the process control loop.

Furthermore, for point sources, an improved thickness uniformity – as a function of source to substrate distance – may limit the material utilization.

The filling level of the point source itself plays an important role in their emission characteristic and the required homogeneous temperature distribution, at least for thermal sensitive materials in order to avoid hot spots, spreading etc., is significantly improved using linear evaporators. Furthermore, linear evaporators are suitable for top-down and bottom-up deposition.

Several of these point source related challenges in high-volume manufacturing systems can be overcome by the introduction of linear evaporation sources.

Benefits of VON ARDENNE linear evaporators:

1. Advanced design enables various configurations (geometry & temperature) to meet the evaporation parameters of inorganic/organic based absorber materials as well as organic contact layers, which are required to achieve an effective perovskite cell,
2. Achieves industrial relevant dynamic deposition rates
3. Offers an excellent coating uniformity independent from coating width and material filling level
4. Uses inert (corrosion resistant) material for all parts in contact with the evaporation material

The VON ARDENNE perovskite team invites you to further elaborate on the success factors of linear thermal evaporation. You will find the contact information here.

¹ “Vapor phase deposition of perovskite photovoltaics: short track to commercialization?”