Casting the Right Shadow

Science for Everyone – PD Dr. Alexander Pwalis

Smartphones, cars and lighting systems all depend on more and more semiconductors. Making them is an industrial marathon that leaves traces — in the quality of the components and in their environmental footprint. A clever technology from Jülich could change that by putting “shadow walls” in exactly the right place.

June 2026

_{The Prototype: Creating the shadow that interrupts the material flux. This brick-built model illustrates the principle behind the shadow wall technology in a tangible way. It was built especially for us by Dr. Pawlis's seven-year-old son.}

A Pathway for Semiconductors

Inside every smartphone are tiny components that direct current, create light and process signals. Without them, nothing works: no display, no sensors, no processor. These components are made of semiconductors, and they do not appear as finished blocks. They grow layer by layer.

To make them, a component travels through a factory line that resembles an obstacle course: coating, structuring, etching, cleaning — and then the same sequence again. “It is a top-down process, and every step can damage the material,” explains Privatdozent Dr. Alexander Pawlis.

In conventional production, systems first deposit complete material layers across a silicon wafer. Only afterwards do machines painstakingly carve the structure into shape, etching away unwanted material and cleaning the remains. Several masks have to be positioned one after another with extreme precision. Even a tiny misalignment on the nanometre scale can shift electrical contacts out of place.

Because the components leave the protective vacuum several times during this journey, they come into contact with air. They can oxidize or become contaminated. The traces remain in the semiconductor. “Taken together, they make components less efficient. You notice it when energy escapes as heat instead of becoming computing power or light — or when the parts go straight to scrap,” says Pawlis.

„In Jülich, we develop things for the world after tomorrow. Companies often become interested later, but then all the more intensely.”

PD Dr. Alexander Pwalis

Bottom-Up: Semiconductors That Grow Into Shape

Pawlis, who heads a research group at the Peter Grünberg Institute — Semiconductor Nanoelectronics (PGI-9), wants to shorten the obstacle course. His solution for the chip factory of tomorrow is shadow wall technology, also known as shadow wall epitaxy.

Instead of depositing broad layers and laboriously removing what is not needed, Pawlis takes a bottom-up approach. The device grows directly into its final form. At the very beginning, tiny structures — the shadow walls — are placed on the wafer. They stop unwanted material from forming in the first place, so machines no longer have to remove it later with highly toxic solvents, acids and etchants.

The semiconductor materials are heated and evaporated in high vacuum. With no air molecules in the way, the atoms travel in a precise, directional beam, almost like a laser, towards the wafer. There they settle as a thin layer. The walls act like shade-casters: Pawlis aligns them exactly with the angle of the atomic beam, so they intercept the material flow in selected areas. The surface behind the walls remains bare, while the exposed regions grow the desired structures layer by layer.

Because only one initial mask is needed — and that mask can even come from a 3D printer — later alignment errors and tolerance problems disappear. Even the metal contacts grow directly in place. The device leaves the protective vacuum only once it is fully finished, in an all-in-situ process. Air and contamination never get a chance.

Enable more efficient semiconductor manufacturing

The prototype

The model creates the shadow that interrupts the material flow. Built from interlocking bricks, it makes the principle of shadow walls easy to grasp. Pawlis’s seven-year-old son built it for us.

The Economic Lever

“The approach saves time and energy and prevents the manufacturing process from damaging the material. Chips made this way work more efficiently, generate hardly any heat and last much longer,” Pawlis says. It also saves resources. Because shadow wall technology reduces the production chain, and with it the machines and materials required, it produces far less toxic waste — from heavy-metal-contaminated solvents to alkaline and acidic solutions.

Pawlis has already shown that the principle works at laboratory scale. The next step is to adapt the technology for existing industrial production lines. “It is still future music,” he says — and for him, that is normal. “In Jülich, we develop things for the world after tomorrow. Companies often become interested later, but then all the more intensely.” With shadow walls, that tomorrow has already begun. Together with the industry partner ELEMENT 3-5, Pawlis wants to build the bridge from laboratory to factory.

The economic leverage is considerable. Shadow walls could cut manufacturing costs by roughly 30 percent on top of other savings. ELEMENT 3-5 has already managed to produce components at 300 °C instead of the usual 1,000 °C, which has a major impact on energy costs. For this innovation, the company won the TOP 100 Innovation Award in 2025. Overall, the process could end up around half as expensive as conventional methods — with higher throughput because typical production errors fall away.

A Chip Monopoly in the Shadows?

Together, Pawlis and ELEMENT 3-5 want to contribute to European semiconductor production and reduce dependence on Asian chip monopolies. Their semiconductors could appear almost everywhere in daily life: in highly efficient LEDs, in power transistors for electric cars, in sensors.

So if the smartphone of the future stays cooler and needs charging less often, the reason may lie in a few cleverly placed shade-casters from Jülich.

Shadow Wall Epitaxie: Growth of Tomorrow

PD Dr. Alexander Pawlis
heads the Semiconductor Epitaxy and Quantum Optics research group at the Peter Grünberg Institute (PGI-9) and leads the institute's research activities in innovative shadow wall technology.
To the Pawlis Research Group (PGI-9)

Dr. Yurii Kutovyi
is the architect behind the shadow wall technology within Dr. Pawlis's team at PGI-9.
To the Team at PGI-9

^{Image Credits: Alexander Pawlis; Forschungszentrum Jülich}

Mehrere Geräte, ein Gehirn und zerknülltes Papier auf orangefarbenem Hintergrund. (Mistral: Mistral Medium 3.5, 2026-06-30)

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