Abstract: A micromachined microphone is formed from a silicon or silicon-on-insulator (SOI) wafer. A fixed sensing electrode for the microphone is formed from a top silicon layer of the wafer. Various polysilicon microphone structures are formed above a front side of the top silicon layer by depositing at least one oxide layer, forming the structures, and then removing a portion of the oxide underlying the structures from a back side of the top silicon layer through trenches formed through the top silicon layer. The trenches allow sound waves to reach the diaphragm from the back side of the top silicon layer. In an SOI wafer, a cavity is formed through a bottom silicon layer and an intermediate oxide layer to expose the trenches for both removing the oxide and allowing the sound waves to reach the diaphragm. An inertial sensor may be formed on the same wafer, with various inertial sensor structures formed at substantially the same time and using substantially the same processes as corresponding microphone structures.

Abstract: A method of processing a semiconductor wafer provides a wafer, and then forms an organic mask on at least a portion of the wafer. The method then applies a vapor etching process to the wafer through holes in the organic mask.

Abstract: A SOI-based MEMS device has a base layer, a device layer, and an insulator layer between the base layer and the device layer. The device also has a deposited layer having a portion that is spaced from the device layer. The device layer is between the insulator layer and the deposited layer.

Abstract: Rather than increasing the mass of the structure, the structure in a sensor system suspends its substrate from some mechanical ground. Motion of the substrate relative to the mechanical ground thus provides the movement information. To those ends, the sensor system includes a base, a substrate, and a flexible member suspended from at least a portion of the substrate. At least a portion of the flexible member is capable of moving relative to at least a portion of the substrate. In addition, the flexible member is secured to the base, thus causing the substrate to be movable relative to the base. Moreover, the mass of the substrate is greater than the mass of the flexible member. The substrate and flexible member are configured to interact to produce a motion signal identifying movement of the base.

Abstract: A method of forming a MEMS device first releases structure, relative to a substrate, to form a space between the structure and the substrate. The process then adds material to the space between the structure and the substrate to substantially stabilize the structure relative to the substrate. Then, at some subsequent point, the method removes at least a portion of the material from the space to re-release the structure.

Abstract: A SOI-based MEMS device has a base layer, a device layer, and an insulator layer between the base layer and the device layer. The device also has a deposited layer having a portion that is spaced from the device layer. The device layer is between the insulator layer and the deposited layer.

Abstract: A method of forming a MEMS device provides a wafer having a base, a first conductive layer, a second conductive layer, and an intermediate conductive layer. After it provides the wafer, the method removes at least a portion of the intermediate conductive layer to form a cavity between the first and second conductive layers. At least a portion of the first conductive layer is movable relative to the base to form a diaphragm, while the second conductive layer is substantially immovable relative to the base. After it forms the cavity, the method seals the cavity.