Quantum Sentinel for Power Electronics express
A power transistor made of silicon carbide operates under voltages thousands of times higher than what comes out of a wall outlet. If the field inside it becomes uneven, the device burns out. Previously, this field was invisible: it is too strong for ordinary sensors, and the device must remain under voltage. Now, a tiny spy has been found in the crystal — a defect that glows in response to the field.
This defect is a vacancy where a silicon atom should be. Such a vacancy behaves like a compass needle: its glow changes depending on the direction of the field. Remarkably, the needle senses the field equally well both along and across the crystal. It's like a compass that not only shows north but also altitude. No other sensor does this.
Spectroscopy of the vacancy's glow allows mapping the field inside the device with a resolution of less than a micrometer. You can locate where the field gathers into a dangerous "fist" and redesign the device so that the blow lands on a stronger spot. This approach turns power electronics development from trial and error into an exact science.
Original abstract
as written by the authors arXiv:2603.13836
For high-bias operation devices such as silicon carbide (SiC) power devices, early detection of failure mechanisms is essential to ensure reliability. This requires a method to map high electric fields with high spatial resolution, which has not been realized until now. Here we report that the silicon vacancy (Vsi) in SiC has outstanding characteristics for detecting electric fields applied in various directions within a high-biased SiC device. Vsi exhibits an equivalent response to electric field components parallel (Epara) and perpendicular (Eperp) to the c-axis, a feature unique among quantum sensors, and the responsiveness to Epara and Eperp enables detection of arbitrary electric fields encountered in cutting-edge SiC power devices. We confirmed high electric field detection of ~2.3 MV/cm, which is ~90% of the breakdown electric field of a 4H-SiC with typical carrier concentration. Selectively formed Vsi enables high-resolution mapping of electric field distribution. Vsi-based quantum sensors bring data-driven research and development methodologies as well as device degradation diagnosis.
A single silicon vacancy in silicon carbide is smaller than one millionth of a millimeter, yet it can report on a field thousands of times stronger than the field inside a thundercloud.