Atomic Limits company talk: SALD and their spatial ALD business

An interview with Bas van de Loo and Peter Visser

This is the start of a new series of blog posts in which we will share exciting information about companies or other organizations within the atomic scale processing industry. By means of interviews we try to present not only a general idea about the focus of these organizations, but also dig deeper into their thoughts about the atomic scale processing industry and how it will develop in the future. Part of the items addressed originate from our own point of view and interests and therefore we will also report on their vision about science communication and how they can be of interest for students, and vice versa.

The first company that we are very excited to announce is SALD situated in Eindhoven, The Netherlands. SALD develops machines that create functional nanolayers by means of spatial ALD, also abbreviated as SALD and hence their name. In spatial ALD a substrate moves through different zones in which it is exposed to vapors to build up layers, in contrast to regular ALD where the substrate is static and only one gas is dosed at a time. This approach enables a high throughput at low costs, which is most promising for sustainable energy innovations. SALD originated as a so called carve out from another company called SoLayTec, which has over 10 years of experience in the production of spatial ALD machines for solar panels. In order to investigate new applications and to look beyond the single purpose of solar panels, a new identity needed to be created and the company SALD was born.

Facts and Figures about SALD
Company location	Eindhoven
Year established	2019
Markets	Solar, battery, electrolysis and packaging industries
Main collaborations	TU/e, TU Delft, Coatema and VDL ETG
Main disciplines	Physicists, mechanical engineers, construction and electronic technicians
Number of employees 2022	16
Number of employees 2021	14
Student opportunities	Yes! They always have openings for students from virtually all technical disciplines and from all education levels
Goal for 2022	Having the roll-to-roll technology fully developed and sold, giving clients major competitive advantages

**Figure 1**: Peter Visser (left) and Bas van de Loo (right) in front of their spatial atomic layer deposition testing machine, while holding one of their 3D printed components.

What kind of projects is SALD working on?

While selling their existing spatial ALD machines with their unique patented technology, SALD is also continuously improving processes and developing promising new technologies. In general, we can currently divide their work into four major parts:

Sampling process
Selling an ALD machine is nothing like, for example, simply selling a printer from a media shop. Due to its complexity and tunability, a whole process resolves around the sale, which they call the sampling process. A client that is interested will first want to try it out on their own substrate, to see if it works on the desired material. This also means that SALD has to adjust the specific process to the client, in which for example a new substrate is used, or other layer properties and thicknesses or equipment sizes are required. The machine can therefore be completely adjusted in collaboration with the customers.

Continuous process development for new applications
SALD has noticed that the industry is moving towards green sustainable energy innovations and that many promising and successful projects can be done in this field. Worldwide these technologies still require a lot of work and this could be a perfect opportunity for The Netherlands to play a leading role in this field. This is also why SALD is continuously researching new applications of spatial ALD. This includes for example also functionalization of membranes for fuel cells, electrolyzers and even direct carbon capture.

Roll-to-roll process of spatial ALD
Instead of having to move the substrate back and forth, as typically done in many spatial ALD machines, the goal is to have a continuous movement of very long (for example 100 meter) flexible foils as substrate. This can be compared to the fabrication of newspapers, in which the paper is guided over such large rolls. Apparently, there is high demand from the industry for these machines and it has been an ambition of SALD for a long time. Right now, they are testing the fabrication of ‘a single newspaper’ and are hoping to get the machine ready for larger throughput soon.

High temperature plasma sources
Together with other industrial suppliers, SALD is developing high temperature plasma sources, which can withstand high deposition temperatures in the ALD process. They are currently testing the functionality of different sources from different suppliers and how these can contribute to new applications.

**Figure 2**: Close-up of SALD’s spatial ALD equipment.

What are unique features of SALD?

A visit to the assembly station immediately shows how many options and possibilities a spatial ALD machine has. Here, many tubes for different gases are connected and can be tested and many different shapes and sizes of nozzles can be found (from which the gas flows onto the substrate). Something unique about SALD is that both the development and design on paper, as well as the assembly happen in nearly the same room, only separated by a door or two. This means that if during the construction a problem occurs, the mechanic can immediately discuss this with the engineer and a new design can be made on the spot. The parts are ordered and produced somewhere else, yet SALD assembles all the machines by itself in its own facility.

Another characteristic is that they use 3D printing for some complex components. This way many different shapes and sizes can be created and the whole machine becomes very scalable. Most of the time they first print components in plastic to try them out, before they eventually print them in stainless steel, which is more elaborated and expensive. These 3D printed parts are ordered externally, for which Eindhoven happens to be a very good supply area.

**Figure 3**: A complete spatial ALD system made by SALD.

Who are the main clients and how does SALD deal with competition?

Most of the clients are currently situated outside of Europe, which vary from large companies to small start-ups and R&D institutes. Especially photovoltaics seems an active area for these clients, which is a strong asset of SALD since they still have many strong connections and a good reputation of the mother company SoLayTec. Within Europa they noticed that the covid crisis led to a temporary closure of many labs and therefore also no new equipment was bought for a while.

Within the Eindhoven Brainport region a lot of ALD activity is happening, yet SALD seems to look mostly at the bright sight of this competition. First of all, because of their philosophy that if you’re the only one doing something, it is probably not a good idea. Also, they rely on their own strengths and notice that the market is currently large enough for many ALD equipment suppliers. Especially in the research phase, a lot of collaboration can be beneficial and having a second competing supplier can strengthen their own position.

In general, the goal is to create a larger market collectively, for example in fuel cells. The best way to accomplish this is to create more awareness of the usefulness of spatial ALD and how this technique can contribute to making products less expensive. More people need to be educated and it needs to be understandable for a larger audience, also those who do not have a scientific background. Peter is a perfect example for this and he notices that this doesn’t have to be hard. He has no problem understanding the technical concepts even though he has a business background.

Which local or governmental initiatives could be useful?

When looking at the bigger picture, for example in fuel cells, the layers created with spatial ALD are only a small part of the whole chain of the production. All the different parties involved in the development need to work together to create high quality end products and to make an impact on the existing market. For SALD it would be very beneficial if for example the growth fund proposal NextGen HighTech in the Netherlands would be approved. This proposal includes a program in which batteries are manufactured with ALD layers.

Apart from funding, there are also many scientific questions that need to be answered. Examples are: What is the best way to deposit in 3D structures? Or the best way to deposit on flexible substrates or membranes? Even though SALD is doing research by themselves, there are also many fields that are too challenging to jump into right now. Their opinion is that a large part of the research these days is focused on applications and this should more often be from a technological perspective. The low TRL (technology readiness level) activities should get enough attention, which implies more long-term research.

SALD aims to do this by themselves in the future once they have enough budget and employees to facilitate their own characterization laboratory. Until then, they rely on other organizations, such us the TU/e and TNO, to perform long-term research. However, it is not self-evident that these organizations continue the focus on ALD. Therefore, it is again important to create a larger market such that more budget can be spend on research in this area.

Does SALD actively pay attention to science communication?

As mentioned before, creating more awareness about spatial ALD and a better understanding about the concept is definitely beneficial to SALD. There are a few common approaches that they are currently working on themselves in terms of science communication, such as participating in science and technical conferences, for example by giving presentations and publishing these materials in proceedings. Besides, they attend trade fairs and send out press releases. They also recently renewed their website and created a new logo.

Figure 4: SALD’s new logo.

When looking at their target audience, they don’t focus on the general public, but rather on a specific group that already has knowledge about the subject. This is of course directly related to the fact that only a specific group of people actually buys these ALD machines, and it is not like a television that you can try to sell to every random person. However, they do feel that a broader audience would be useful, yet this is more of a long-term goal.

What is your experience with student internships?

The past year about 5-10 students have performed internships or graduation projects at SALD. These students had very different backgrounds, such as physics, computer science, mechatronics, mechanical engineering, or business administration, all with different levels of education.

According to SALD, the great benefit of working there is the small-scale character of this company. You are not only doing the job you were hired for, but you also see and learn from all the other aspects that are involved in running a company. One moment you can be performing demo ALD tests on a substrate and the next moment you might be joining a sales meeting with a potential client.

This also requires students and employees to be very independent and assertive. The attitude and the way in which someone tackles problems is generally more important than just having a lot of knowledge about the subjects. In fact, they don’t feel at all that incoming students lack important knowledge, yet especially students with a technology background have a tendency to be very precise and feel the need to figure everything out in the smallest detail. However, the goal of SALD is not to answer scientific questions, it is to build a working machine, and not everything needs to be completely understood as long as it works in a specific range. So, the biggest lesson for students is often to look beyond their own work and to see how their part fits into the complete picture. And also using a simple multimeter can sometimes be a real hassle for those who only studied from books!