WHAT DISTINGUISHES YOUR DIAMONDS FROM OTHER ARTIFICIAL DIAMONDS?

Normal diamonds consist of carbon atoms arranged in a crystal lattice structure. In our production process, we exchange a carbon atom for a nitrogen atom and remove a neighboring carbon atom. This combination of a nitrogen atom and vacancy in the diamond lattice is known as the nitrogen-vacancy center, or NV center for short. An NV center can be used to capture electrons whose properties can be used for quantum measurement technology. Usually, electrons are constantly interacting with their environment, but the surrounding diamond structure isolates the electrons so that they can only interact with our samples. This makes it possible to effectively determine the quantum state of the electrons.

WHAT DOES THE QUANTUM STATE OF AN ELECTRON TELL YOU?

We take a look at the electron spin. This is influenced by magnetic fields. We can tell very precisely where a magnetic field is located and how strong it is because there are millions of NV centers in each diamond, which we read out optically at the same time. So we really do make magnetic fields visible.

HOW SO?

Our diamond fluoresces. We shine a green laser on it and the NV centers light up red. We use the green laser to feed energy into the NV centers, and the NV centers release the energy again in the form of red light, which we record with a camera. The crucial question is how bright or dark is the red light? This is because the brightness of the red light enables us to draw conclusions about the magnetic field. And not only that. With NV sensor technology, we can also measure other things, such as very precise temperatures.

WHAT ARE YOUR DIAMOND SENSORS USED FOR?

We are currently concentrating primarily on failure analysis of semiconductors. If a company develops a new chip that doesn’t work, we can test it with our diamond sensor. The result is an image on which we can display the magnetic field in high resolution. This allows you to see exactly how the electric current flows within the semiconductor or to see where there is a problem. For failure analysis, it is important to gain visual access to the problem area. You cannot see through the metal layers of the chip with a normal microscope. However, magnetic fields penetrate everything completely. With our method, we can therefore make flows and problems visible that would otherwise be invisible.

DOES THIS MEAN THAT COMPANIES SEND YOU SEMICONDUCTOR CHIPS FOR FAILURE ANALYSIS?

Yes, failure analysis is currently carried out as a service in our laboratory. In 2025, however, we will also be selling a Quantum Diamonds microscope. This allows companies to carry out the failure analysis themselves. At the same time, we want to develop a product for quality control on the production lines. On the production line, it's not about a detailed failure analysis, but about whether the chip works or not. Together with various Fraunhofer Institutes, we want to work on the fastest possible measurement. Our aim is to launch a product on the market around 2028 that will be ready for the production line. The market for failure analysis is large, but the market for manufacturing is even larger and growing all the time. That would be a huge leap for us if we could achieve that.

QUANTUM DIAMONDS OFFERS NOT ONLY THE MEASUREMENT OF MAGNETIC FIELDS AND TEMPERATURES, BUT ALSO WIDEFIELD IMAGING. WHAT DOES THAT MEAN?

If I want to make an image of a very small object – in other words, take a magnified photo of it – I normally have two options. The first option is: I look through a normal microscope. When I do this, I can see the whole object at once – that’s basically the definition of widefield imaging. However, the resolution of my picture is limited. If I want a better resolution, I can use the second option: I scan many points of the object one after the other – pixel by pixel, so to speak. The result is higher resolution, but the process is time-consuming. It can take days or even weeks to scan the entire object. We have found a widefield option at Quantum Diamonds that allows you to record a very good resolution directly.

WHAT DOES THAT MEAN?

Widefield imaging is normally limited to a resolution of 500 nanometers. That sounds very small, but a semiconductor has structures that can be much smaller. For comparison: The classic scanning method achieves a resolution of 30 nanometers. It’s much smaller, but you can’t cover a very large field of view with it or the complete scanning would take an extremely long time. We used the SPRIND funds to produce a hemispheric diamond lens that bundles the light so that we can achieve a resolution of 180 nanometers with a measurement duration of 10 minutes. This resolution is very interesting for the semiconductor industry because we cover an intermediate range between the other two methods. If there is a problem on the chip, we can either see the problem area directly, or we can at least narrow down the failure area so that only the relevant area needs to be scanned – this speeds up the failure analysis considerably.

WHAT MOTIVATES YOU PERSONALLY IN YOUR WORK?

I like physics, I like technical things, and I like to think about things. But it was always important to me to have an applied use behind what I’m doing, and it’s great to see how our measurements work. Thanks to SPRIND funding, our progress has been rapid. Sometimes you’re completely immersed in everyday life, you solve a problem that exists right now and it seems slow, but then you think back a month, half a year and then you realize: Wow, progress is actually super fast. And that’s really what I think is the coolest thing right now.

Mehr über Quantum Diamonds: www.quantumdiamonds.de