Analog Devices,inc.

Bradley C Kaanta

Jeffrey A Gregory

Charles Blackmer

Nikolay Pokrovskiy

Kemiao Jia

Microelectromechanical system (MEMS) inertial sensors exhibiting reduced parasitic capacitance are described. The reduction in the parasitic capacitance may be achieved by forming localized regions of thick dielectric material. These localized regions may be formed inside trenches. Formation of trenches enables an increase in the vertical separation between a sense capacitor and the substrate, thereby reducing the parasitic capacitance in this region. The stationary electrode of the sense capacitor may be placed between the proof mass and the trench. The trench may be filled with a dielectric material. Part of the trench may be filled with air, in some circumstances, thereby further reducing the parasitic capacitance. These MEMS inertial sensors may serve, among other types of inertial sensors, as accelerometers and/or gyroscopes. Fabrication of these trenches may involve lateral oxidation, whereby columns of semiconductor material are oxidized.

Low-parasitic capacitance MEMS inertial sensors and related methods

A capacitive microelectromechanical systems (MEMS) sensor is provided, having conductive coatings on opposing surfaces of capacitive structures. The capacitive structures may be formed of silicon, and the conductive coating is formed of tungsten in some embodiments. The structure is formed in some embodiments by first releasing the silicon structures and then selectively coating them in the conductive material. In some embodiments, the coating may result in encapsulating the capacitive structures.

Selective conductive coating for MEMS sensors

A MEMS device has a substrate with a structure surface and an opposing exterior surface, microstructure formed on the structure surface of the substrate, and a cap coupled with the substrate to form a hermetically sealed interior chamber containing the microstructure. The substrate forms a trench extending from, and being open to, the opposing exterior surface to produce a sensor region and a second region. Specifically, the second region is radially outward of the sensor region. The MEMS device also has a spring integrally formed at least in part within the trench to mechanically connect the sensor region and the second region, and other structure integral with the substrate. The spring or the other structure at least in part hermetically seal the interior chamber.

Mechanically isolated MEMS device

Various embodiments produce a semiconductor device, such a MEMS device, having metallized structures formed by replacing a semiconductor structure with a metal structure. Some embodiments expose a semiconductor structure to one or more a reacting gasses, such as gasses including tungsten or molybdenum.

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Belmont, MA, United States of America

Bradley C Kaanta