A surface of a cavity of a MEMS device that is rough to reduce stiction. In some embodiments, the average roughness (Ra) of the surface is 5 nm or greater. In some embodiments, the rough surface is formed by forming one or more layers of a rough oxidizable material, then oxidizing the material to form an oxide layer with a rough surface. Another layer is formed over the oxide layer with the rough surface, wherein the roughness of the oxide layer is transferred to the another layer.

Various embodiments of the invention provide for stiction testing in MEMS devices, such as accelerometers. In certain embodiments, testing is accomplished by a high voltage smart circuit that enables an analog front-end circuit to accurately read the position of a movable proof-mass relative to a biased electrode in order to allow the detection of both contact and release conditions. Testing allows to detect actual or potential stiction failures and to reject defective parts in a Final Test stage of a manufacturing process where no other contributors to stiction issue can occur, thereby, minimizing stiction failure risks and extending the reliability of MEMS devices.

A physical quantity sensor includes a physical quantity detection circuit having a determination circuit that determines whether a value of a physical quantity signal continuously remains within a predetermined range in a predetermined period, determines that a physical quantity detection element is in a first state of normal operation when the value does not continuously remain, and determines that the physical quantity detection element is in a second state of abnormal operation when the value continuously remains, a control circuit that stores first information based on a determination result of the determination circuit is stored in a control circuit as a setting information and a communication section that outputs the setting information stored in from the control circuit to the outside when the determination result of the determination circuit indicates the second state.

According to one embodiment, a method for controlling a vibration device includes a movable body capable of vibrating in a first direction, and a catch and release mechanism capable of catching the movable body that freely vibrates in the first direction, by an electrostatic attractive force, and releasing the caught movable body to freely vibrate the movable body in the first direction, wherein in a condition that tc is a time from a rise start time point to a rise end time point of an applied voltage for catching the movable body that freely vibrates in the first direction, by the electrostatic attractive force, and td is a period of the free vibration in the first direction of the movable body, the time tc is longer than the time td.

A physical quantity sensor includes a physical quantity detection circuit having a determination circuit that determines whether a value of a physical quantity signal continuously remains within a predetermined range in a predetermined period, determines that a physical quantity detection element is in a first state of normal operation when the value does not continuously remain, and determines that the physical quantity detection element is in a second state of abnormal operation when the value continuously remains, a control circuit that stores first information based on a determination result of the determination circuit is stored in a control circuit as a setting information and a communication section that outputs the setting information stored in from the control circuit to the outside when the determination result of the determination circuit indicates the second state.

A MEMS device comprising a substrate comprising a die and a plurality of side-walls disposed upon the MEMS die, a proof-mass coupled to the substrate, the proof-mass is configured to be displaced within a first plane that is parallel to the die, wherein the proof-mass is configured to contact at least a sidewall, wherein the proof-mass is configured to adhere to the side-wall as a result of stiction forces, a driving circuit configured to provide a driving voltage in response to a driving signal indicating that the proof-mass is adhered to the side-wall, and an actuator coupled to the driving circuit disposed upon the side-wall, wherein the actuator is configured to receive a driving voltage and to provide an actuator force to the proof mass within the first plane in a direction away from the side-wall in response to the driving voltage, wherein the actuator force exceeds the stiction forces.

Capped microelectromechanical systems (MEMS) devices are described. In at least some situations, the MEMS device includes one or more masses which move. The cap may include a stopper which damps motion of the one or more movable masses. In at least some situations, the stopper damps motion of one of the masses but not another mass.

According to one embodiment, a method for controlling a vibration device includes a movable body capable of vibrating in a first direction, and a catch and release mechanism capable of catching the movable body that freely vibrates in the first direction, by an electrostatic attractive force, and releasing the caught movable body to freely vibrate the movable body in the first direction, wherein in a condition that tc is a time from a rise start time point to a rise end time point of an applied voltage for catching the movable body that freely vibrates in the first direction, by the electrostatic attractive force, and td is a period of the free vibration in the first direction of the movable body, the time tc is longer than the time td.

Capped microelectromechanical systems (MEMS) devices are described. In at least some situations, the MEMS device includes one or more masses which move. The cap may include a stopper which damps motion of the one or more movable masses. In at least some situations, the stopper damps motion of one of the masses but not another mass.

Capped microelectromechanical systems (MEMS) devices are described. In at least some situations, the MEMS device includes one or more masses which move. The cap may include a stopper which damps motion of the one or more movable masses. In at least some situations, the stopper damps motion of one of the masses but not another mass.