Thin-Film-Based SAW Magnetic Field Sensors
Jana Meyer, Viktor Schell, Jingxiang Su, Simon Fichtner, Erdem Yarar, Florian Niekiel, Thorsten Giese, Anne Kittmann, Lars Thormählen, V. Lebedev, Stefan Moench, Agnė Žukauskaitė, Eckhard Quandt, Fabian Lofink
Abstract
In this work, the first surface acoustic-wave-based magnetic field sensor using thin-film AlScN as piezoelectric material deposited on a silicon substrate is presented. The fabrication is based on standard semiconductor technology. The acoustically active area consists of an AlScN layer that can be excited with interdigital transducers, a smoothing SiO2 layer, and a magnetostrictive FeCoSiB film. The detection limit of this sensor is 2.4 nT/Hz at 10 Hz and 72 pT/Hz at 10 kHz at an input power of 20 dBm. The dynamic range was found to span from about ±1.7 mT to the corresponding limit of detection, leading to an interval of about 8 orders of magnitude. Fabrication, achieved sensitivity, and noise floor of the sensors are presented.