Abstract: A MEMS device (40) includes a base structure (42) and a microstructure (44) suspended above the structure (42). The base structure (42) includes an oxide layer (50) formed on a substrate (48), a structural layer (54) formed on the oxide layer (50), and an insulating layer (56) formed over the structural layer (54). A sacrificial layer (112) is formed overlying the base structure (42), and the microstructure (44) is formed in another structural layer (116) over the sacrificial layer (112). Methodology (90) entails removing the sacrificial layer (112) and a portion of the oxide layer (50) to release the microstructure (44) and to expose a top surface (52) of the substrate (48). Following removal, a width (86) of a gap (80) produced between the microstructure (44) and the top surface (52) is greater than a width (88) of a gap (84) produced between the microstructure (44) and the structural layer (54).

Abstract: Embodiments of compact micro-electro-mechanical systems (MEMS) devices are provided, as are embodiments of methods for fabricating MEMS devices. In one embodiment, the MEMS device includes a substrate, a movable structure resiliently coupled to the substrate, and an anchored structure fixedly coupled to the substrate. The movable structure includes a first plurality of movable fingers, and a second plurality of movable fingers electrically isolated from and interspersed with the first plurality of movable fingers. The anchored structure includes fixed fingers interspersed with first and second pluralities of movable fingers in a capacitor-forming relationship. First and second interconnects are electrically coupled to the first and second pluralities of movable fingers, respectively.

Abstract: A MEMS sensor (20, 86) includes a support structure (26) suspended above a surface (28) of a substrate (24) and connected to the substrate (24) via spring elements (30, 32, 34). A proof mass (36) is suspended above the substrate (24) and is connected to the support structure (26) via torsional elements (38). Electrodes (42, 44), spaced apart from the proof mass (36), are connected to the support structure (26) and are suspended above the substrate (24). Suspension of the electrodes (42, 44) and proof mass (36) above the surface (28) of the substrate (24) via the support structure (26) substantially physically isolates the elements from deformation of the underlying substrate (24). Additionally, connection via the spring elements (30, 32, 34) result in the MEMS sensor (22, 86) being less susceptible to movement of the support structure (26) due to this deformation.

Abstract: A MEMS device (40) includes a base structure (42) and a microstructure (44) suspended above the structure (42). The base structure (42) includes an oxide layer (50) formed on a substrate (48), a structural layer (54) formed on the oxide layer (50), and an insulating layer (56) formed over the structural layer (54). A sacrificial layer (112) is formed overlying the base structure (42), and the microstructure (44) is formed in another structural layer (116) over the sacrificial layer (112). Methodology (90) entails removing the sacrificial layer (112) and a portion of the oxide layer (50) to release the microstructure (44) and to expose a top surface (52) of the substrate (48). Following removal, a width (86) of a gap (80) produced between the microstructure (44) and the top surface (52) is greater than a width (88) of a gap (84) produced between the microstructure (44) and the structural layer (54).

Abstract: A MEMS device (40) includes a base structure (42) and a microstructure (44) suspended above the structure (42). The base structure (42) includes an oxide layer (50) formed on a substrate (48), a structural layer (54) formed on the oxide layer (50), and an insulating layer (56) formed over the structural layer (54). A sacrificial layer (112) is formed overlying the base structure (42), and the microstructure (44) is formed in another structural layer (116) over the sacrificial layer (112). Methodology (90) entails removing the sacrificial layer (112) and a portion of the oxide layer (50) to release the microstructure (44) and to expose a top surface (52) of the substrate (48). Following removal, a width (86) of a gap (80) produced between the microstructure (44) and the top surface (52) is greater than a width (88) of a gap (84) produced between the microstructure (44) and the structural layer (54).

Abstract: An inertial sensor (20) includes a drive mass (30) configured to undergo oscillatory motion and a sense mass (32) linked to the drive mass (30). On-axis torsion springs (58) are coupled to the sense mass (32), the on-axis torsion springs (58) being co-located with an axis of rotation (22). The inertial sensor (20) further includes an off-axis spring system (60). The off-axis spring system (60) includes off-axis springs (68, 70, 72, 74), each having a connection interface (76) coupled to the sense mass (32) at a location on the sense mass (32) that is displaced away from the axis of rotation (22). Together, the on-axis torsion springs (58) and the off-axis spring system (60) enable the sense mass (32) to oscillate out of plane about the axis of rotation (22) at a sense frequency that substantially matches a drive frequency of the drive mass (30).

Abstract: A MEMS device (20) includes a proof mass (32) coupled to and surrounding an immovable structure (30). The immovable structure (30) includes fixed fingers (36, 38) extending outwardly from a body (34) of the structure (30). The proof mass (32) includes movable fingers (60), each of which is disposed between a pair (62) of the fixed fingers (36, 38). A central area (42) of the body (34) is coupled to an underlying substrate (24), with the remainder of the immovable structure (30) and the proof mass (32) being suspended above the substrate (24) to largely isolate the MEMS device (20) from package stress, Additionally, the MEMS device (20) includes isolation trenches (80) and interconnects (46, 50, 64) so that the fixed fingers (36), the fixed fingers (38), and the movable fingers (60) are electrically isolated from one another to yield a differential device configuration.

Abstract: A MEMS sensor (20, 86) includes a support structure (26) suspended above a surface (28) of a substrate (24) and connected to the substrate (24) via spring elements (30, 32, 34). A proof mass (36) is suspended above the substrate (24) and is connected to the support structure (26) via torsional elements (38). Electrodes (42, 44), spaced apart from the proof mass (36), are connected to the support structure (26) and are suspended above the substrate (24). Suspension of the electrodes (42, 44) and proof mass (36) above the surface (28) of the substrate (24) via the support structure (26) substantially physically isolates the elements from deformation of the underlying substrate (24). Additionally, connection via the spring elements (30, 32, 34) result in the MEMS sensor (22, 86) being less susceptible to movement of the support structure (26) due to this deformation.

Abstract: Embodiments of compact micro-electro-mechanical systems (MEMS) devices are provided, as are embodiments of methods for fabricating MEMS devices. In one embodiment, the MEMS device includes a substrate, a movable structure resiliently coupled to the substrate, and an anchored structure fixedly coupled to the substrate. The movable structure includes a first plurality of movable fingers, and a second plurality of movable fingers electrically isolated from and interspersed with the first plurality of movable fingers. The anchored structure includes fixed fingers interspersed with first and second pluralities of movable fingers in a capacitor-forming relationship. First and second interconnects are electrically coupled to the first and second pluralities of movable fingers, respectively.

Abstract: An inertial sensor (20) includes a drive mass (30) configured to undergo oscillatory motion and a sense mass (32) linked to the drive mass (30). On-axis torsion springs (58) are coupled to the sense mass (32), the on-axis torsion springs (58) being co-located with an axis of rotation (22). The inertial sensor (20) further includes an off-axis spring system (60). The off-axis spring system (60) includes off-axis springs (68, 70, 72, 74), each having a connection interface (76) coupled to the sense mass (32) at a location on the sense mass (32) that is displaced away from the axis of rotation (22). Together, the on-axis torsion springs (58) and the off-axis spring system (60) enable the sense mass (32) to oscillate out of plane about the axis of rotation (22) at a sense frequency that substantially matches a drive frequency of the drive mass (30).

Abstract: A MEMS device (20) includes a proof mass (32) coupled to and surrounding an immovable structure (30). The immovable structure (30) includes fixed fingers (36, 38) extending outwardly from a body (34) of the structure (30). The proof mass (32) includes movable fingers (60), each of which is disposed between a pair (62) of the fixed fingers (36, 38). A central area (42) of the body (34) is coupled to an underlying substrate (24), with the remainder of the immovable structure (30) and the proof mass (32) being suspended above the substrate (24) to largely isolate the MEMS device (20) from package stress, Additionally, the MEMS device (20) includes isolation trenches (80) and interconnects (46, 50, 64) so that the fixed fingers (36), the fixed fingers (38), and the movable fingers (60) are electrically isolated from one another to yield a differential device configuration.

Abstract: A MEMS device (40) includes a base structure (42) and a microstructure (44) suspended above the structure (42). The base structure (42) includes an oxide layer (50) formed on a substrate (48), a structural layer (54) formed on the oxide layer (50), and an insulating layer (56) formed over the structural layer (54). A sacrificial layer (112) is formed overlying the base structure (42), and the microstructure (44) is formed in another structural layer (116) over the sacrificial layer (112). Methodology (90) entails removing the sacrificial layer (112) and a portion of the oxide layer (50) to release the microstructure (44) and to expose a top surface (52) of the substrate (48). Following removal, a width (86) of a gap (80) produced between the microstructure (44) and the top surface (52) is greater than a width (88) of a gap (84) produced between the microstructure (44) and the structural layer (54).

Abstract: A MEMS device (20) includes a substrate (22), a proof mass (28), and a frame structure (30) laterally spaced apart from the proof mass (28). Compliant members (36) are coupled to the proof mass (28) and the frame structure (30) to retain the proof mass (28) suspended above the surface (26) of the substrate (22) without directly coupling the proof mass (28) to the substrate (22). Anchors (32) suspend the frame structure (30) above the surface (26) of the substrate (22) without directly coupling the structure (30) to the substrate (22), and retain the structure (30) immovable relative to the substrate (22) in a sense direction (42). The compliant members (36) enable movement of the proof mass (28) in the sense direction (42). Movable fingers (38) extending from the proof mass (28) are disposed between fixed fingers (46) extending from the frame structure (30) to form a differential capacitive structure.

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 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).