3d mems magnetometer and associated methods

A 3D MEMS magnetometer for measuring first, second and third magnetic field components respectively along mutually orthogonal first, second and third axes, the 3D MEMS magnetometer comprising:

• a MEMS wafer having opposed top and bottom sides, the MEMS wafer comprising a frame structure and current-carrying first, second and third magnetic field transducers, the MEMS wafer being a silicon-on-insulator wafer with a MEMS device layer, a MEMS handle layer, and a MEMS insulating layer interposed between the MEMS device layer and the MEMS handle layer, the first, second and third magnetic field transducers being formed in the MEMS device layer;
• a top cap wafer and a bottom cap wafer respectively bonded to the MEMS device layer and the MEMS handle layer, the top cap wafer, the bottom cap wafer and the MEMS wafer being electrically conductive, the top cap wafer, the bottom cap wafer and the frame structure forming, in combination, one or more cavities, each cavity enclosing at least one of the first, second and third magnetic field transducers, each magnetic field transducer being enclosed in one of the one or more cavities;
• and
• first, second and third electrode assemblies, the first and second electrode assemblies each being formed in the top cap wafer, each of the first, second and third electrode assemblies being configured to sense an output of a respective one of the first, second and third magnetic field transducers induced by a respective one of the first, second and third magnetic field components.

A method for measuring first, second and third magnetic field components along mutually orthogonal first, second and third axes, respectively, the method comprising:

• operating a three-dimensional (3D) micro-electro-mechanical system (MEMS) magnetometer comprising a MEMS wafer having opposed top and bottom sides, the MEMS wafer comprising a frame structure and current-carrying first, second and third magnetic field transducers, a top cap wafer and a bottom cap wafer respectively bonded to the top side and the bottom side of the MEMS wafer, the top cap wafer, the bottom cap wafer and the MEMS wafer being electrically conductive, the top cap wafer, the bottom cap wafer and the frame structure forming, in combination, one or more cavities, each cavity enclosing at least one of the first, second and third magnetic field transducers, each magnetic field transducer being enclosed in one of the one or more cavities;
• flowing current into each of the first, second and third magnetic field transducers;
• and
• sensing an output of each the first, second and third magnetic field transducers induced by and indicative of a respective one of the first, second and third magnetic field components.