Magnetoelectric Flexural Gate Transistor With Nanotesla Sensitivity

Magnetic sensors capable of detecting tiny ac magnetic fields ranging from microtesla to picotesla are of great interest. In this paper, we demonstrate an integrated magnetoelectric (ME) flexural gate transistor with nanotesla magnetic field detection sensitivity at room temperature. The device capacitively couples a Metglas (Fe
_0.85
B
_0.05
Si
_0.1
)-based magnetostrictive unimorph micromechanical cantilever beam to the gate of an n-channel field-effect transistor. Using this sensor configuration, a sensitivity of 0.23 mV/μT and a minimum detectable field of 60 nT/√Hz at 1 Hz and 1.5 mV/μT and 150 pT/√Hz at the flexural resonance of the cantilever structure of 4.9 kHz were obtained. The results demonstrate a significant improvement in the thin-film ME sensor integration with standard CMOS process and open the possibility of monolithic magnetic sensor arrays fabrication for biomedical imaging applications.