The Silicon Review
The ever-increasing computer processing power has created the information society that we have today, where power consumption is now a key parameter – not only for increasing performance – but also for mobility as well as sustainability. Obviously, the semiconductor industry will have to modify its basic building block, the transistor, due to fundamental physical limits on efficiency. The use of magnetic materials will be essential to overcome these limitations.
A prime example of innovation is magnetic random access memory (MRAM), which is on-track to replace the power-hungry RAM in a computer and uses only 1% of the former’s energy. Devised in the 1980s and 1990s and commercialized by Everspin, MRAM is now in the line-up of every major semiconductor manufacturer. Moving in a similar direction, a paper published by Intel in 2018 shows transistor replacements based on magnetic materials that reduce power consumption by more than an order of magnitude while, at the same time, being smaller than current transistors. So, we will see the benefits from the research of magnetic materials at the nanometer scale transform into longer-lasting mobile devices and less power-hungry data centers in the future.
Zurich-based Nanotech Company QZabre might have the solution that provides a powerful tool for the much-needed research in memory materials. The company innovates through its cutting-edge work in NV magnetometry, which is a powerful quantum technology for R&D at the nanometer scale.
In a brief interview with us, the CEO of QZabre, Dr. Gabriel Puebla-Hellmann, told us about the importance of NV magnetometry and how QZabre is leading the innovation at this crucial intersection of science and technology. He also talked to us about the company’s flagship Quantum Scanning Microscope (QSM), the next-generation scanning probe microscope based on QZabre’s diamond quantum sensor technology. Read on for the excerpts from the interview.
Q. For our readers, could you tell us what NV magnetometry is?
NV magnetometry uses a single atomic defect in diamond, a Nitrogen-Vacancy center (NV), to quantitatively map magnetic fields at the nanometer scale. The NV is essentially an atom “frozen” inside the diamond, creating a quantum bit that is very sensitive to its environment, especially to magnetic fields. We manipulate this defect using microwave pulses to extract this information with very high sensitivity. The excellent spatial resolution is a combination of the sensor atomic sizeand the fact that we scan the sensor over the surface at a height of only a few nanometers. Our quantum scanning microscope is a robust, desktop-sized system that runs under ambient conditions. The QSM offers a combination of high sensitivity and spatial resolution that is typically only be achieved with large-scale infrastructure, like synchrotrons, in a high-vacuum environment.
Q. What are the applications of scanning NV magnetometry?
Scanning NV magnetometry is a powerful new tool for R&D at the nanometer scale. The most obvious area of application are magnetic nanostructures and textures, such as skyrmions, magnetic racetracks, or MRAM devices. NV magnetometry is so sensitive that it can map the stray field of a single atomic layer, as found in antiferromagnetic materials or two-dimensional ferromagnets, enabling both static and dynamic characterization of magnetic patterns, like the movement of vortices.
The second major field of application is the tracing of currents in nanoscale integrated circuits. At the transistor size and density in today’s computer chips, thermal management is a crucial issue, often related to how much current flows where. Current tracing also helps pinpoint defects, enabling semiconductor manufacturers to understand different modes of failures in a chip. Beyond simple mapping, it is also possible to use the NV as an atomic-sized oscilloscope, providing data as a function of time rather than space. Lastly, NV is an upcoming technology that is still actively researched, with possible applications in chemical analysis, biological imaging and medical diagnosis.
Q. Tell us about QSM. What can it do that other microscopes cannot?
Our goals when creating the QSM were threefold: first, to create a powerful magnetic microscope that is turn-key and allows the user to focus on measuring his sample, rather than fiddling with technology. NV magnetometry is a complex technology combining atomic force microscopy, microwave electronics, and optical readout. The QSM product design and software support the user in efficiently setting up measurements, automating many of the complex calibration routines. We have incorporated several hardware innovations, such as a dual imaging system, which enable the user to quickly change samples, setup the system and orient himself on the sample. The software guides the user through the different setup steps and we are working on automating many of these steps.
Our second design goal was to offer the best possible measurement sensitivity. Currently, acquiring quantitative magnetic images can take hours and ultimately, the range of samples that can be studied will be limited by the sensitivity that the system can achieve. The sensitvity is limited by the quality of the diamond probes, which are a key focus of our R&D, but hardware optimization also offers significant gains.
Third, our QSM uses a flexible, modular design. It offers customers a degree of customization that is not available elsewhere. For example, we offer several hardware extensions including to advanced measurement modes or vector magnet modules that enable magnetic manipulation of the sample. In summary, the QSM is an easy-to-use system with the highest sensitivity and most flexible design on the market.
Q. How important are partnerships to what you do as a company?
Developing and engineering a novel type of instrument is a very challenging task that is not possible without excellent partners. We are a spin-off from the Spin Physics group at ETH Zurich and our partnership with Prof. Degen, the Principle Investigator, has been essential in starting up the company. An NV magnetometer such as the QSM requires many different parts which we can’t engineer ourselves and are supplied by other companies. Wherever possible, we partnered with the suppliers, extending both their and our own knowledge, leading to design improvements and mutually beneficial business relationship.
Q. What does innovation mean to QZabre?
The fundamental working principle of NV magnetometry is a combination of several different fields. For us, innovation is what happens at the meeting point of different technologies, backgrounds and philosophies. Finding new angles to attack a common problem requires expanding one’s horizon and our team with its multitude of technical and ethnic background is a great place to do that.
Q. What can we expect from QZabre in near future?
Near term, we strive to improve NV magnetometry to the point that it becomes a fast and standard imaging method when looking at magnetic probes – similar to atomic force microscopy. Between hardware and software, there are still significant improvements to be made. In the long term, we will diversify and use our know-how to leverage the sensitivity and large dynamic range of NVs in other applications. We won the Zeiss Quantum Challenge in industrial metrology early this year. Our proposal uses NV centres to determine the position of an object and its orientation with micrometer precision over a cubic meter volume without requiring line-of-sight. Used for applications in high-precision manufacturing, it highlights the versatility of quantum sensing with NVs.