Fabrication of Sensitive MEMS-based Magnetometer for Biomagnetic Applications*

The electrocardiogram (ECG) is the standard method of heart disease detection but is inconveniently sized and susceptible to conductive tissue noise and signal attenuation by filtering. Additionally, the superconducting quantum interference device (SQUID) systems operate in vacuum, are expensive and large, and are rivaled by atomic magnetometers (AMs), which are compact and sensitive but limited by spin relaxation. Here we report the development and fabrication of a MEMS-based, 100pT/cm sensitive, inexpensive magnetometer device, which may overcome the mentioned limitations. The device measures gradient fields by detecting magnetic force exerted on a commercial MEMS capacitive accelerometer through the coupled micro-sized, permanent magnet. Present limitations of this device are fabrication throughput and magnet characterization. Here we discuss characterization by a vibrating sample magnetometer (VSM) and obstacles in a custom micro-gluing technique.