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A microelectromechanical device and method of fabricating the same, including a layer of patterned and deposited metal or mechanical-quality, doped polysilicon inserted between the appropriate device element layers, which provides a conductive layer to prevent the microelectromechanical device's out

A microelectromechanical device and method of fabricating the same, including a layer of patterned and deposited metal or mechanical-quality, doped polysilicon inserted between the appropriate device element layers, which provides a conductive layer to prevent the microelectromechanical device's output from drifting. The conductive layer may encapsulate of the device's sensing or active elements, or may selectively cover only certain of the device's elements. Further, coupling the metal or mechanical-quality, doped polysilicon to the same voltage source as the device's substrate contact may place the conductive layer at the voltage of the substrate, which may function as a Faraday shield, attracting undesired, migrating ions from interfering with the output of the device.

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1. A semiconductor microelectromechanical device comprising:a substrate; a sensing element formed on the substrate, wherein the sensing element includes a moveable part; and a conductive shield formed atop at least a portion of the moveable part of the sensing element such that the conductive shield

1. A semiconductor microelectromechanical device comprising:a substrate; a sensing element formed on the substrate, wherein the sensing element includes a moveable part; and a conductive shield formed atop at least a portion of the moveable part of the sensing element such that the conductive shield is operable to move along with the at least a portion of the movable part of the sensing element, wherein the conductive shield is coupled to the substrate, and wherein the conductive shield is formed so as to not introduce non-compensatable error into the sensing element when the movable part of the sensing element moves. 2. The semiconductor microelectromechanical device of claim 1, wherein the conductive shield comprises doped silicon.3. The semiconductor microelectromechanical device of claim 2, wherein the conductive shield comprises doped polysilicon.4. The semiconductor microelectromechanical device of claim 3, wherein the conductive shield comprises doped, elastic polysilicon.5. The semiconductor microelectromechanical device of claim 1, further including an insulating layer formed between the sensing element and the conductive shield.6. The semiconductor microelectromechanical device of claim 5, wherein the insulating layer comprises an oxide film.7. The semiconductor microelectromechanical device of claim 5, wherein the insulating layer comprises a silicon dioxide (SiO2) film.8. The semiconductor microelectromechanical device of claim 1, further including a passivation layer formed over the conducting layer.9. The semiconductor microelectromechanical device of claim 1, wherein the conductive shield coupled to the substrate is placed at substantially the same voltage as the substrate.10. The semiconductor microelectromechanical device of claim 1, wherein the conductive shield and the substrate provide a complete encapsulation of the sensing element.11. The semiconductor microelectromechanical device of claim 10, wherein the conductive shield and the substrate are coupled together at a node, and wherein the node is operable to be placed at substantially the same voltage as the substrate.12. The semiconductor microelectromechanical device of claim 10, wherein the conductive shield and the substrate are coupled together at a node, and wherein the node is operable to be placed at a substantially constant voltage.13. The semiconductor microelectromechanical device of claim 10, wherein the conductive shield and the substrate are coupled together at a node, and wherein the node is operable to be placed at a varying voltage.14. The semiconductor microelectromechanical device of claim 10, wherein the substrate comprises at least one node, the at least one node providing a ground voltage, wherein the sensing element formed over the substrate has a ground voltage, wherein the sensing element formed over the substrate is coupled to the substrate, and wherein the conductive shield that is coupled to the substrate is placed at about the ground voltage of the node of the substrate.15. The semiconductor microelectromechanical device of claim 10, wherein the sensing element comprises a first output that provides a first signal in response to an external force, semiconductor microelectromechanical device further including a second output that provides a second signal having a maximum output voltage proportional to the first signal, and wherein the conductive shield that is coupled to the substrate is placed at a voltage greater than the maximum output voltage of the second signal.16. The semiconductor microelectromechanical device of claim 1, wherein the conductive shield formed atop the substrate provides a partial encapsulation of the sensing element.17. The semiconductor microelectromechanical device of claim 16 wherein the conductive shield and the substrate are coupled together at a node, and wherein the node is operable to be placed at substantially the same voltage as the substrate.18. The semiconductor microelectromechanical device of claim 16 wherein the conductive shield and the substrate are coupled together at a node, and wherein the node is operable to be placed at a substantially constant voltage.19. The semiconductor microelectromechanical device of claim 16 wherein the conductive shield and the substrate are coupled together at a node, and wherein the node is operable to be placed at a varying voltage.20. The semiconductor microelectromechanical device of claim 16, wherein the substrate comprises at least one node, the at least one node providing a ground voltage, wherein the sensing element formed over the substrate has a ground voltage, wherein the sensing element formed over the substrate is coupled to the substrate, and wherein the conductive shield that is coupled to the substrate is placed at about the ground voltage of the node of the substrate.21. The semiconductor microelectromechanical device of claim 16, wherein the sensing element comprises a first output that provides a first signal in response to an external force, semiconductor microelectromechanical device further including a second output that provides a second signal having a maximum output voltage proportional to the first signal, and wherein the conductive shield that is coupled to the substrate is placed at a voltage greater than the maximum output voltage of the second signal.22. The semiconductor microelectromechanical device of claim 1, wherein the conductive shield is doped to a low resistivity.23. The semiconductor microelectromechanical device of claim 1, wherein the substrate comprises a silicon wafer, wherein conductive shield is formed atop the sensing element and at least one part of the silicon wafer substrate, and wherein the conductive shield is coupled to the silicon wafer substrate.24. A semiconductor microelectromechanical device comprising:a first-type-dopant substrate; a second-type-dopant epitaxial layer; at least one sensing element formed in a portion of the second-type-dopant epitaxial layer, wherein the at least one sensing element includes a movable part, an insulating layer formed over at least one portion of the at least one sensing element; a conductive-polysilicon layer formed atop at least portion of the movable part of the sensing element such that the conductive shield is operable to move along with the at least a portion of the movable part of the sensing element, wherein the conductive shield is formed so as to not Introduce non-compensatable error into the sensing element when the movable part of the sensing element moves; a passivation layer formed over the first-type-dopant substrate; and at least one via formed between the conductive polysilicon layer and the first-type-dopant substrate, wherein the conductive polysilicon layer is coupled to the first-type-dopant substrate through the at least one via. 25. The semiconductor microelectromechanical device of claim 24, wherein the conductive-polysilicon layer and the first-type-dopant substrate are placed at substantially the same voltage.26. The semiconductor microelectromechanical device of claim 24, further including an enclosure, and a strap, wherein the strap couples the first-type-dopant substrate and the enclosure.27. The semiconductor microelectromechanical device of claim 26, wherein the enclosure is placed at a constant potential.28. The semiconductor microelectromechanical device of claim 24, further including:a second-type-dopant region in the first-type-dopant substrate; and at least one conductive plug provided in the at least one via coupling the conductive-polysilicon layer and the second-type-dopant region, wherein the conductive-polysilicon layer and the second-type-dopant region are placed at substantially the same potential. 29. A semiconductor microelectromechanical device comprising:a substrate; a top-epitaxial layer formed over the substrate; a thermal-oxide layer grown over at least a portion of the top-epitaxial layer; at least one runner patterned and etched in at least a portion of the thermal-oxide layer; a sensing element formed in the top-epitaxial layer; and a conductive shield formed over at least a portion of the sensing element. 30. The semiconductor microelectromechanical device of claim 29, further including a metalization-interconnection system, wherein the metalization-interconnection system interconnects the conductive-shield layer to the substrate.31. The device of claim 30, wherein the semiconductor microelectromechanical device is selected from a group consisting of pressure sensors, accelerometers, humidity sensors, automotive sensors, current sensors, fiber optic sensors, force sensors, infrared sensor, mass airflow sensors, photosensors, proximity sensors, level sensors, temperature sensors, turbidity sensors, magnetoresistive sensors, magnetic random access memories or ultrasonic sensors.32. The device of claim 30, wherein the semiconductor microelectromechanical device comprises a silicon on insulator pressure sensor.33. The method of claim 32, wherein the top-epitaxial layer is formed to a thickness of about 9000 Å.34. The device of claim 32, wherein the thermal-oxide layer is grown to a thickness of about 13800 Å.35. The device of claim 32, wherein the conductive shield comprises a first-conductive-shield layer, and wherein the first-conductive-shield layer is formed to a thickness of about 1500 Å at approximately 610 degrees Celsius.36. The method of claim 35, wherein the conductive shield further comprises a second-conductive-shield layer, and wherein the second-conductive-shield layer is formed to a thickness of about 1500 Å at approximately 598 degrees Celsius.