text: Quantum Diamonds: Shaping the Future of Diamond-Based Quantum Sensors
  Quantum states are so fragile that they make a house of cards look like a fortress.
  Their fragility makes quantum computing notoriously tricky. But it comes in handy for sensing physical quantities like a magnetic field that disturbs a quantum state. Although fundamental research has been ongoing for decades, it has become possible to engineer practically useful quantum sensors only in the past few years.
  Quantum Diamonds uses diamonds to build quantum sensors that detect magnetic fields and other physical quantities with unprecedented accuracy, helping chipmakers ensure that more of their microchips actually work.
  Founded by Kevin Berghoff, Kristina Liu, and Fleming Bruckmaier in 2022, it raised €3M in Seed funding led by IQ Capital and Earlybird in late 2023. They were joined by Onsight Ventures, First Momentum Ventures, Creator Fund, UnternehmerTUM, and various angel investors. In addition, the European Innovation Council (EIC) Accelerator and the Bavarian state have provided €4M in grants, and Quantum Diamonds was part of the Intel Ignite accelerator program.
  Learn more about the future of diamond-based quantum sensing from our interview with the co-founder and CEO, Kevin Berghoff:
  Why Did You Start Quantum Diamonds?
  After studying business, I spent three years in management consulting at McKinsey. Yet, even though I do not come from a tech background myself, like many others, I noticed that Germany produces a lot of research, but comparatively few people make the effort to bring it into applications. Just think of the MP3 as one of many inventions made in Germany but successfully commercialized outside of it.
  Instead of complaining about how bad things are, I decided to take action and enrolled at TU Munich for a Ph.D. in entrepreneurship, which would give me a chance to engage with many research groups and potentially find one that I could support spinning out their research findings into a deep tech startup.
  As you’d expect, many researchers are rather focused on their research and don’t see the value of a business co-founder. Yet, many aspects of company building are independent of the specific technology you’re developing, so it’s crucial to have business expertise in the team to bring a technology to market successfully.
  I talked a lot to UnternehmerTUM and interviewed more than 50 scientific teams at TU Munich for my PhD research. Then, I did a big Excel comparison of all the research groups and rated them on how advanced their technology was, how far along they were in the spin-out process, how well the personal fit was, and other criteria. Eventually, I found a great match with my now co-founders, Fleming and Kristina, two PhDs in quantum sensing.
  When you think about it, a lot of human progress came from being able to sense things better—being able to detect new chemicals, diseases, or distortions of space-time to calibrate our global GPS. They had developed next-generation sensors ready for commercial applications, which could be another leap in how accurately humanity could sense things. That’s when we decided to go all in two years ago and found Quantum Diamonds.
  How Do Your Quantum Sensors Work?
  Quantum effects are useful not just for computing but also for building sensors with unparalleled sensitivity. Quantum computing is hard because quantum states are fragile and easily destroyed when a quantum system interacts with its environment. Quantum sensing leverages that quantum states are so fragile to measure physical quantities such as magnetic fields, pressure, or temperature non-destructively and much more precisely than classical sensors.
  We use nitrogen-vacancy (NV) centers in diamonds, a type of defect in their crystal structure, consisting of a nitrogen atom adjacent to a vacant site that a carbon atom would normally occupy. Magnetic and electric fields, as well as temperature, alter the electronic states of an NV center easily, which makes them such great nanoscale sensors.
  Papers on diamond-based sensing have been published for decades, but only in the past few years has it become possible to engineer them and actually build useful quantum sensors. A few recent papers have explored industry-specific applications and signaled that the technology has become ripe to move from research to address these applications.
  Besides resolution, the speed of sensing matters, especially for the applications we want to target in the semiconductor industry. Atomic force microscopes also give you high-resolution measurements, but they are very slow—checking a single wafer with nanometer resolution would take weeks, if not months, that way. Our technology will be the only way to measure physical properties on a nanometer scale, but in fractions of a second, and be compatible with the throughput requirements of semiconductor manufacturing.
  Why Quantum Sensing and Not Quantum Computing?
  Quantum sensing can address commercial applications already today. This is much more exciting to me than having to do years of research, such as in quantum computing, before being able to address a business case.
  Quantum supremacy, i.e., when quantum computers outperform supercomputers, has been pushed forward multiple times. It seems always like just five more years into the future, yet it’s unclear when that future will arrive. Many quantum startups are more like privately funded research projects.
  On the contrary, no more fundamental research is needed to bring our technology to customers. Of course, we continue developing it and closely monitor how the research landscape develops. For example, sensors based on NV-centers in silicon could be much cheaper and thus address use cases beyond semiconductor manufacturing. But so far, diamond-based sensing has been the most established and best understood, and we have all the expertise in our team to build a product for the semiconductor industry today.
  How Did You Evaluate Your Startup Idea?
  We put out a white paper exploring different applications for quantum sensing in biology, navigation systems, and semiconductors. In principle, we can sell to all of them. Yet, it quickly turned out that the opportunity in semiconductors may be the largest: we talked to several big names in the industry and learned that fast, high-resolution measurements could be a game changer for inspecting microchips.
  Whenever electric current flows, it generates a magnetic field—so by measuring the magnetic field distribution of a microchip, we can see if the microchip works as expected or whether there are any leakage currents. That way, we could help fabs improve their yield, i.e., the share of functioning chips compared to the overall production, and optimize their chip designs in the future.
  Whereas in healthcare, regulation and customer adoption take a long time, Intel’s analysis lab has already inspected the first microchips using our sensors. We can clearly see a pull from the semiconductor industry and that we are building something people want.
  The opportunity in the semiconductor industry is giant, especially if we manage to get in line. Just imagine placing a Quantum Diamond microscope for chip inspection after each ASML lithography machine. We can get there if we show fabs that we can systematically increase their yields, and then it becomes a no-brainer to use our solution.
  We mapped the different foci of different fabs and started talking to the ones known to be more open and innovation-driven. However, we found that even large semiconductor players are very open to talk: Advanced packing, interconnects, and stacking of components make microchip fabrication increasingly more tricky, and they’re all trying to maintain high yields. Finally, understanding the current distribution is also crucial for developing microchips based on novel semiconductor materials such as gallium nitride or silicon carbide.
  What Advice Would You Give Fellow Deep Tech Founders?
  After you read a couple of entrepreneurship books, put them aside and go talk to people in the real world. We only found out what we needed to focus on when we summarized what we had learned in a white paper and talked to people in the field. Researchers put out cool papers about fancy new things, but you need to find out what people actually need and would pay for. You need to get to problem-solution fit.