Research | IKZ | 03-03-2021

Crystal-clear strategies for a sustainable future

Many of the environmentally friendly technologies we use are made with efficient power electronics. Europe is currently recognising just how important it is to research and produce these electronics locally.

Panorama of the semiconductor growth hall of IKZ, in the foreground (rechts) the new float zone growth facility FZ-30 | IKZ

Globalization, digitalization, climate change – and now the pandemic. Ordinarily highly lucrative, producing goods as cheaply as possible on other continents turns out to be a bad idea in times of crisis. Having urgently needed medicines manufactured in India or China, for example, or buying surgical masks out of Asia alone becomes a problem for Europe when supply chains grind to a halt. And when it comes to the key components of modern high tech, Europe should be singing a song of “sovereignty instead of dependency,” says Thomas Schröder, Director of the Leibniz-Institut für Kristallzüchtung (IKZ). “It’s not about everyone exclusively doing their own thing. Rather, it is about identifying the things we ought to be able to do sufficiently on our own, so as not to be open to manipulation.”

Efforts to re-establish European sources are already being made in the pharmaceutical industry. In Schröder’s view, another industry that could do with some European sovereignty is advanced power electronics. Not only for the technological leadership, but also for the immense amount of money involved.

Electronics start from materials like the ultra-pure semiconductor crystals grown and characterized at IKZ. The market for this in Europe is valued at around 400 billion euro, Schröder states. The corresponding electronics industry, however, is already worth 4.5 trillion euro. And when it comes to the actual applications in digitalisation, social media etc., we are already looking at 50 trillion euro. “So, from the semiconductor crystal to the service provider in the digitalization industry, the value multiplies by a factor of 120!” Simply handing over the lion’s share of the value creation chain to China or the USA is therefore not an option, from an economic standpoint alone.

Digitalization is only one of many application areas. Electronic components are namely needed wherever electricity has to be controlled and converted. Keyword: energy turnaround. “While the solution to rising power demands in the carbon-based energy era was to put up ten new power plants to feed the grid, the renewables sector is going in the direction of decentralized power. Energy generation, transport, conversion, storage and consumption – we need to completely rethink all of these things,” Schröder says. We need smart networks with clever control mechanisms to keep the grids stable. We need efficient electronics to work largely autonomously at all the intersections and interfaces.

Keyword: electromobility. Ever since state subsidies increased, electric cars have been booming. Yet, as simple as it sounds – plug in, charge up, drive off – there are a lot of technologies involved, especially below the surface. Individual electromobility would be inconceivable without power electronics. “At a highway service station, a large amount of energy has to be charged into a car as fast as possible, in around 30 minutes. And not just the one car, but more like hundreds a day, during a typical stream of visitors!” It takes a very high electric current, and only a tiny amount of that is allowed to be lost as heat, otherwise the charging station could explode. Also, many service stations are not located in agglomerated areas, but are out in the “middle of nowhere.” “Accordingly, we have to bring the whole charging infrastructure out to them. This requires entirely new technologies, and ultimately innovative semiconductor crystals for power electronics.”

Different materials must be used for different power requirements. In the low-voltage ranges, the material commonly used is float zone silicon (FZ-Si), which is produced as a high-purity single crystal by the zone melting method. “It is good enough for electromobility. In the higher voltage ranges, however, it becomes less good at blocking leakage current,” Schröder explains. The material that can cope with this is silicon carbide (SiC), for which a company in Erlangen once served the European market. The company has since been bought by a Japanese investor, which preferentially serves its local market in times of material shortage – to the chagrin of European customers. Similar performance is achieved, however, by components made with gallium nitride (GaN). All three crystal “specialities” are being researched at IKZ.

The institute’s focus is currently on gallium oxide (Ga2O3). On paper, the physics of this material should allow it to perform far better still. World-record Ga2O3 transistors were first publicly revealed in Berlin, following a joint research effort of IKZ, CrysTec and the Ferdinand-Braun-Institut. There are no components in technological production yet; industry-standard prototypes will have to be researched over the coming years. Semiconductor crystals that are coming into their own, and whose future will bring exciting new technologies, have the greatest leverage in the value creation chain. “Getting in early on filing patents, publishing academic papers, developing processes and technologies, and then moving on to commercialization through tech transfer to companies or our own start-ups – that is our goal,” says Thomas Schröder. Like many things, technological sovereignty starts small: with a single crystal.

Text: Catarina Pietschmann


Leibniz-Institut für Kristallzüchtung

Stefanie Grüber
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