AlScN-based MEMS magnetoelectric sensor

摘要

MEMS sensors based on magnetoelectric composites have attracted great interest due to their capability to detect weak magnetic fields, showing high potential in applications like biomagnetic field detection and magnetic particle imaging. This paper reports on a scandium aluminum nitride thin film-based MEMS magnetoelectric sensor. The sensor consists of a polycrystalline silicon cantilever with a size of 1000 μm × 200 μm covered by a piezoelectric Al_(0.73)Sc_(0.27)N and a magnetostrictive (Fe_(90)Co_(10))_(78)Si_(12)B_(10) thin film. The performance of the presented sensor is investigated based on the magnetoelectric (ME) voltage coefficient, voltage noise density, and limit of detection and compared to the characteristics of the aluminum nitride thin film-based ME sensor with the same layout and fabrication technology. By using an Al_(0.73)Sc_(0.27)N thin film with a higher piezoelectric activity instead of A1N in MEMS ME sensors, the ME voltage coefficient of (1334 ± 84) V/cm Oe in resonance is almost double, thereby lowering the requirements for the electronic system. The limit of detection of (60 ± 2) pT/Hz~(0.5) remains unchanged due to the dominant thermomechanical noise in resonance.