Semiconductor sensor with piezoresistors and improved electrostatic structures
First Claim
1. An electromechanical sensor comprising:
- an n type semiconductor region which defines a thin flexible member adjacent to a thicker more rigid base portion;
at least one piezoresistor;
at least one n+ region formed in the base portion;
a first insulative layer which overlays said piezoresistor and which extends between said piezoresistor and said first n+ doped region;
a guard layer formed from an electrically conductive material having a coefficient of thermal expansion in the range of approximately (0 to 15 ppm/°
C) and which is disposed over at least a portion of said first insulative layer so as to overlay said at least one piezoresistor; and
a bias contact disposed in the base portion which electrically interconnects said n+ region and said guard layer.
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Accused Products
Abstract
An electromechanical sensor is provided which comprises an n-type semiconductor region which defines a flexible member surrounded by a thicker base portion; at least one piezoresistor formed in the semiconductor region; an n+ region formed in the thicker base portion; a first insulative layer which overlays the piezoresistor and which extends at least from the piezoresistor to the first n+ doped region; a guard layer which overlays at least a portion of the first insulative layer such that the guard layer overlays the piezoresistor and extends at least from the piezoresistor to a point adjacent to the n+ region; and a first bias contact which electrically interconnects the n+ region and the guard layer.
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Citations
23 Claims
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1. An electromechanical sensor comprising:
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an n type semiconductor region which defines a thin flexible member adjacent to a thicker more rigid base portion; at least one piezoresistor; at least one n+ region formed in the base portion; a first insulative layer which overlays said piezoresistor and which extends between said piezoresistor and said first n+ doped region; a guard layer formed from an electrically conductive material having a coefficient of thermal expansion in the range of approximately (0 to 15 ppm/°
C) and which is disposed over at least a portion of said first insulative layer so as to overlay said at least one piezoresistor; anda bias contact disposed in the base portion which electrically interconnects said n+ region and said guard layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. An electromechanical sensor comprising:
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an n-type silicon region which defines a flexible member adjacent to a more rigid base portion; at least one piezoresistor formed in the silicon region; at least one first n+ region formed in the base portion; at least one circuit contact disposed in the base portion; and at least one first electrical interconnection interconnecting said at least one circuit contact and said at least one piezoresistor; a first insulative layer which overlays said at least one piezoresistor and said at least one first interconnection and which extends between said at least one piezoresistor and said first n+ region; and an SiCr layer which overlays at least a portion of said first insulative layer such that said SiCr layer overlays said at least one piezoresistor and overlays said at least one first interconnection, said SiCr layer also extending between said piezoresistor and a point adjacent to said first n+ doped region; and a bias contact disposed in the base portion and which electrically interconnects said n+ region and said SiCr layer. - View Dependent Claims (16, 17, 18)
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19. An electromechanical sensor comprising:
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an n-type silicon region which defines a thin flexible member adjacent to a thicker more rigid base portion; a Wheatstone bridge circuit formed in the silicon region and including at least four circuit elements, each circuit element including, a respective piezoresistor, a respective n+ region formed in the base portion, a respective guard layer formed from an electrically conductive material having a coefficient of thermal expansion in the range of approximately (0 to 15 ppm/°
C), anda respective bias contact which electrically interconnects the respective n+ region and the respective guard layer; and a first insulative layer disposed between the respective guard layers and the respective piezoresistors; wherein said respective guard layers are spaced apart from each other. - View Dependent Claims (20, 21, 22, 23)
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Specification