Abstract: An acceleration sensor includes a semiconductor substrate, a first layer formed on the substrate, a first aperture within the first layer, and a beam coupled at a first end to the substrate and suspended above the first layer for a portion of the length thereof. The beam includes a first boss coupled to a lower surface thereof and suspended within the first aperture, and a second boss coupled to an upper surface of the second end of the beam. A second layer is positioned on the first layer over the beam and includes a second aperture within which the second boss is suspended by the beam. Contact surfaces are positioned within the apertures such that acceleration of the substrate exceeding a selected threshold in either direction along a selected axis will cause the beam to flex counter to the direction of acceleration and make contact through one of the bosses with one of the contact surfaces.

Abstract: A released-beam sensor includes a semiconductor substrate having a layer formed thereon, and an aperture formed in the layer. A beam is mechanically coupled at a first end to the layer and suspended above the layer such that a second end forms a cantilever above the aperture. A boss is coupled to a second end of the beam and suspended at least partially within the aperture. The beam is configured to flex in response to acceleration of the substrate along a vector substantially perpendicular to a surface of the substrate. Parameters of the sensor, such as the dimensions of the beam, the mass of the boss, and the distance between the boss and a contact surface within the aperture, are selected to establish an acceleration threshold at which the boss will make contact with the contact surface. The sensor may be employed to deploy an airbag in a vehicle.

Abstract: An acceleration sensor includes a semiconductor substrate, a first layer formed on the substrate, a first aperture within the first layer, and a beam coupled at a first end to the substrate and suspended above the first layer for a portion of the length thereof. The beam includes a first boss coupled to a lower surface thereof and suspended within the first aperture, and a second boss coupled to an upper surface of the second end of the beam. A second layer is positioned on the first layer over the beam and includes a second aperture within which the second boss is suspended by the beam. Contact surfaces are positioned within the apertures such that acceleration of the substrate exceeding a selected threshold in either direction along a selected axis will cause the beam to flex counter to the direction of acceleration and make contact through one of the bosses with one of the contact surfaces.