Abstract: A pressure transducer includes a substrate, a piezoresistive element, a first conductive element, a first terminal, and a test structure. The substrate has a surface and a cavity. A diaphragm layer is formed over the cavity and over the surface of the substrate. The piezoresistive element is formed in the diaphragm layer. The first conductive element is formed in the diaphragm layer, and has a first conductivity type. The first conductive element is coupled to the piezoresistive element. The first terminal is formed over a surface of the diaphragm layer and coupled to the first conductive element. The test structure has the first conductivity type and is formed in the diaphragm layer. The test structure has an edge spaced apart from an edge of the first conductive element by a predetermined distance. A surface charge accumulation on the diaphragm layer is detected using the test structure.

Abstract: A device (20, 90) includes sensors (28, 30) that sense different physical stimuli. A pressure sensor (28) includes a reference element (44) and a sense element (52), and an inertial sensor (30) includes a movable element (54). Fabrication (110) entails forming (112) a first substrate structure (22, 92) having a cavity (36, 100), forming a second substrate structure (24) to include the sensors (28, 30), and coupling (128) the substrate structures so that the first sensor (28) is aligned with the cavity (36, 100) and the second sensor (30) is laterally spaced apart from the first sensor (28). Forming the second structure (24) includes forming (118) the sense element (52) from a material layer (124) of the second structure (24) and following coupling (128) of the substrate structures, concurrently forming (132) the reference element (44) and the movable element (54) in a wafer substrate (122) of the second structure (24).

Abstract: A microelectromechanical systems (MEMS) pressure sensor device (20, 62) includes a substrate structure (22, 64) having a cavity (32, 68) formed therein and a substrate structure (24) having a reference element (36) formed therein. A sense element (44) is interposed between the substrate structures (22, 24) and is spaced apart from the reference element (36). The sense element (44) is exposed to an external environment (48) via one of the cavity (68) and a plurality of openings (38) formed in the reference element (36). The sense element (44) is movable relative to the reference element (36) in response to a pressure stimulus (54) from the environment (48). Fabrication methodology (76) entails forming (78) the substrate structure (22, 64) having the cavity (32, 68), fabricating (84) the substrate structure (24) including the sense element (44), coupling (92) the substrate structures, and subsequently forming (96) the reference element (36) in the substrate structure (24).

Abstract: A method of forming a micro-electromechanical system (MEMS) includes providing a cap substrate, providing a support substrate, depositing a conductive material over the support substrate, patterning the conductive material to form a gap stop and a contact, wherein the gap stop is separated form the contact by an opening, forming a bonding material over the contact and in the opening, wherein the gap stop and the contact prevent the bonding material from extending outside the opening, and attaching the cap substrate to the support substrate by the step of forming the bonding material. In addition, the structure is described.

Abstract: A device structure is made using a first conductive layer over a first wafer. An isolated conductive region is formed in the first conductive layer surrounded by a first opening in the conductive layer. A second wafer has a first insulating layer and a conductive substrate, wherein the conductive substrate has a first major surface adjacent to the first insulating layer. The insulating layer is attached to the isolated conductive region. The conductive substrate is thinned to form a second conductive layer. A second opening is formed through the second conductive layer and the first insulating layer to the isolated conductive region. The second opening is filled with a conductive plug wherein the conductive plug contacts the isolated conductive region. The second conductive region is etched to form a movable finger over the isolated conductive region. A portion of the insulating layer under the movable finger is removed.

Abstract: A method of forming a micro-electromechanical system (MEMS) includes providing a cap substrate, providing a support substrate, depositing a conductive material over the support substrate, patterning the conductive material to form a gap stop and a contact, wherein the gap stop is separated form the contact by an opening, forming a bonding material over the contact and in the opening, wherein the gap stop and the contact prevent the bonding material from extending outside the opening, and attaching the cap substrate to the support substrate by the step of forming the bonding material. In addition, the structure is described.

Abstract: A microelectromechanical systems (MEMS) sensor device (20) includes a substrate (22) having sensors (24, 26) disposed on the same side (28) of the substrate (22) and laterally spaced apart from one another. The sensor (26) includes a sense element (56), and the substrate (22) includes a cavity (58) extending through the substrate (22) from the backside (30) of the substrate (22) to expose the sense element (56) to an external environment (54). The sense element (56) is movable in response to a stimulus (52) from the environment (54) due to its exposure to the environment (54) via the cavity (58). Fabrication methodology (66) entails concurrently forming the sensors (24, 26) on substrate (22) by implementing MEMS process flow, followed by creating the cavity (58) through the substrate (22) to expose the sense element (56) to the environment (54).

Abstract: A microelectromechanical systems (MEMS) device (20) includes a polysilicon structural layer (46) having movable microstructures (28) formed therein and suspended above a substrate (22). Isolation trenches (56) extend through the layer (46) such that the microstructures (28) are laterally anchored to the isolation trenches (56). A sacrificial layer (22) is formed overlying the substrate (22), and the structural layer (46) is formed overlying the sacrificial layer (22). The isolation trenches (56) are formed by etching through the polysilicon structural layer (46) and depositing a nitride (72), such as silicon-rich nitride, in the trenches (56). The microstructures (28) are then formed in the structural layer (46), and electrical connections (30) are formed over the isolation trenches (56). The sacrificial layer (22) is subsequently removed to form the MEMS device (20) having the isolated microstructures (28) spaced apart from the substrate (22).

Abstract: A method for making a MEMS structure comprises patterning recesses in a dielectric layer overlying a substrate, each recess being disposed between adjacent mesas of dielectric material. A conformal layer of semiconductor material is formed overlying the recesses and mesas. The conformal layer is chemical mechanically polished to form a chemical mechanical polished surface, wherein the chemical mechanical polishing is sufficient to create dished portions of semiconductor material within the plurality of recesses. Each dished portion has a depth proximate a central portion thereof that is less than a thickness of the semiconductor material proximate an outer portion thereof. A semiconductor wafer is then bonded to the chemical mechanical polished surface. The bonded semiconductor wafer is patterned with openings according to the requirements of a desired MEMS transducer. Lastly, the MEMS transducer is released.

Abstract: A microelectromechanical systems (MEMS) sensor device (184) includes a sensor portion (180) and a sensor portion (182) that are coupled together to form a vertically integrated configuration having a hermetically sealed chamber (270). The sensor portions (180, 182) can be formed utilizing different micromachining techniques, and are subsequently coupled utilizing a wafer bonding technique to form the sensor device (184). The sensor portion (180) includes one or more sensors (186, 188), and the sensor portion (182) includes one or more sensors (236, 238). The sensors (186, 188) are located inside the chamber (270) facing the sensors (236, 238) also located inside the chamber (270). The sensors (186, 188, 236, 238) are configured to sense different physical stimuli, such as motion, pressure, and magnetic field.

Abstract: A transducer (20) includes sensors (28, 30) that are bonded to form a vertically integrated configuration. The sensor (28) includes a proof mass (32) movably coupled to and spaced apart from a surface (34) of a substrate (36). The sensor (30) includes a proof mass (58) movably coupled to and spaced apart from a surface (60) of a substrate (56). The substrates (36, 56) are coupled with the surface (60) of substrate (56) facing the surface (34) of substrate (36). Thus, the proof mass (58) faces the proof mass (32). The sensors (28, 30) are fabricated separately and can be formed utilizing differing micromachining techniques. The sensors (28, 30) are subsequently coupled (90) utilizing a wafer bonding technique to form the transducer (20). Embodiments of the transducer (20) may include sensing along one, two, or three orthogonal axes and may be adapted to detect movement at different acceleration sensing ranges.

Abstract: A method and apparatus are described for fabricating a high aspect ratio MEMS device by using metal thermocompression bonding to assemble a reference wafer (100), a bulk MEMS active wafer (200), and a cap wafer (300) to provide a proof mass (200d) formed from the active wafer with bottom and top capacitive sensing electrodes (115, 315) which are hermetically sealed from the ambient environment by sealing ring structures (112/202/200a/212/312 and 116/206/200e/216/316).

Abstract: A microelectromechanical systems (MEMS) device (20) includes a polysilicon structural layer (46) having movable microstructures (28) formed therein and suspended above a substrate (22). Isolation trenches (56) extend through the layer (46) such that the microstructures (28) are laterally anchored to the isolation trenches (56). A sacrificial layer (22) is formed overlying the substrate (22), and the structural layer (46) is formed overlying the sacrificial layer (22). The isolation trenches (56) are formed by etching through the polysilicon structural layer (46) and depositing a nitride (72), such as silicon-rich nitride, in the trenches (56). The microstructures (28) are then formed in the structural layer (46), and electrical connections (30) are formed over the isolation trenches (56). The sacrificial layer (22) is subsequently removed to form the MEMS device (20) having the isolated microstructures (28) spaced apart from the substrate (22).

Abstract: A method for making a MEMS structure comprises patterning recesses in a dielectric layer overlying a substrate, each recess being disposed between adjacent mesas of dielectric material. A conformal layer of semiconductor material is formed overlying the recesses and mesas. The conformal layer is chemical mechanically polished to form a chemical mechanical polished surface, wherein the chemical mechanical polishing is sufficient to create dished portions of semiconductor material within the plurality of recesses. Each dished portion has a depth proximate a central portion thereof that is less than a thickness of the semiconductor material proximate an outer portion thereof. A semiconductor wafer is then bonded to the chemical mechanical polished surface. The bonded semiconductor wafer is patterned with openings according to the requirements of a desired MEMS transducer. Lastly, the MEMS transducer is released.

Abstract: A miniaturized micromachined (MEMS) accelerometer-based sensor suitable for use in biological applications, such as a middle ear implant, is provided. An encapsulation layer is deposited on top of an accelerometer proof mass and flexure prior to release of the proof mass and flexure. The encapsulation layer protects the proof mass and flexure from subsequent processing steps, such as dicing and packaging, which enables fabrication of finished devices having reduced size. Surfaces within the accelerometer may be passivated after releasing the proof mass and flexure. Remote piezoresistive sensing is performed in order to provide low noise and reduced sensor head size.

Abstract: A miniaturized micromachined (MEMS) accelerometer-based sensor suitable for use in biological applications, such as a middle ear implant, is provided. An encapsulation layer is deposited on top of an accelerometer proof mass and flexure prior to release of the proof mass and flexure. The encapsulation layer protects the proof mass and flexure from subsequent processing steps, such as dicing and packaging, which enables fabrication of finished devices having reduced size. Surfaces within the accelerometer may be passivated after releasing the proof mass and flexure. Remote piezoresistive sensing is performed in order to provide low noise and reduced sensor head size.