Abstract: Example embodiments of the disclosed technology methods, devices, and systems for compensating a sensor having thermal gradients. In one embodiment, a system is provided that includes a sensor, including a first half-bridge transducer configured to output a first pressure signal associated with a first received pressure; a first set of span resistors coupled to the first half-bridge transducer, and configured generate a first compensated pressure signal; a second half-bridge transducer, configured to output a second pressure signal associated with a second received pressure; and a second set of span resistors coupled to the second half-bridge transducer and configured to generate a second compensated pressure signal. The system includes an output port that is configured to output a signal associated with a difference between the first compensated pressure signal and the second compensated pressure signal.

Abstract: This disclosure provides example methods, devices, and systems for compensating a sensor having thermal gradients.

Abstract: A gage/differential pressure transducer assembly having enhanced output capabilities, comprising a first pressure port adapted to communicate a first pressure to a first sensor, the first sensor comprising a first Wheatstone bridge adapted to output a first signal indicative of the first pressure, wherein the first pressure is a main pressure; and a second pressure port adapted to communicate a second pressure to a second sensor, the second sensor comprising a second Wheatstone bridge adapted to output a second signal indicative of the second pressure, wherein the second pressure is a reference pressure; and an output port connected to the first Wheatstone bridge and the second Wheatstone bridge for outputting a third signal representative of the difference between the first and second pressures.

Abstract: A gage/differential pressure transducer assembly having enhanced output capabilities, comprising a first pressure port adapted to communicate a first pressure to a first sensor, the first sensor comprising a first Wheatstone bridge adapted to output a first signal indicative of the first pressure, wherein the first pressure is a main pressure; and a second pressure port adapted to communicate a second pressure to a second sensor, the second sensor comprising a second Wheatstone bridge adapted to output a second signal indicative of the second pressure, wherein the second pressure is a reference pressure; and an output port connected to the first Wheatstone bridge and the second Wheatstone bridge for outputting a third signal representative of the difference between the first and second pressures.

Abstract: A pressure transducer including: a silicon substrate including: a first surface adapted for receiving a pressure applied thereto, an oppositely disposed second surface, and a flexing portion adapted to deflect when pressure is applied to the first surface; at least a first sensor formed on the second surface and adjacent to a center of the flexing portion, and adapted to measure the pressure applied to the first surface; at least a second gauge sensor formed on the second surface and adjacent to a periphery of the flexing portion, and adapted to measure the pressure applied to the first surface; a glass substrate secured to the second surface of the silicon wafer.

Abstract: A pressure transducer including: a silicon substrate including: a first surface adapted for receiving a pressure applied thereto, an oppositely disposed second surface, and a flexing portion adapted to deflect when pressure is applied to the first surface; at least a first sensor formed on the second surface and adjacent to a center of the flexing portion, and adapted to measure the pressure applied to the first surface; at least a second gauge sensor formed on the second surface and adjacent to a periphery of the flexing portion, and adapted to measure the pressure applied to the first surface; a glass substrate secured to the second surface of the silicon wafer.

Abstract: A pressure transducer including: a silicon substrate including: a first surface adapted for receiving a pressure applied thereto, an oppositely disposed second surface, and a flexing portion adapted to deflect when pressure is applied to the first surface; at least a first sensor formed on the second surface and adjacent to a center of the flexing portion, and adapted to measure the pressure applied to the first surface; at least a second gauge sensor formed on the second surface and adjacent to a periphery of the flexing portion, and adapted to measure the pressure applied to the first surface; a glass substrate secured to the second surface of the silicon wafer.

Abstract: A method of fabricating a high pressure piezoresistive pressure transducer having a substantially linear pressure versus stress output over its full range of operation. The method involves bonding a carrier wafer having a dielectric isolating layer on one surface and a supporting member on the opposite surface, to a pattern wafer containing at least two single crystalline longitudinal piezoresistive sensing elements of a second conductivity. Both the pattern wafer and sections of the carrier wafer are etched leaving the piezoresistive sensing elements bonded directly to the dielectric isolating layer, and a diaphragm member having a deflecting portion and a non-deflecting portion. The diaphragm member is constructed to have an aspect ratio which is of the order of magnitude of one.

Abstract: A method of fabricating a high pressure piezoresistive pressure transducer having a substantially linear pressure versus stress output over its full range of operation. The method involves bonding a carrier wafer having a dielectric isolating layer on one surface and a supporting member on the opposite surface, to a pattern wafer containing at least two single crystalline longitudinal piezoresistive sensing elements of a second conductivity. Both the pattern wafer and sections of the carrier wafer are etched leaving the piezoresistive sensing elements bonded directly to the dielectric isolating layer, and a diaphragm member having a deflecting portion and a non-deflecting portion. The diaphragm member is constructed to have an aspect ratio which is of the order of magnitude of one.

Abstract: A semiconductor transducer structure is fabricated by utilizing varying height diffused layers in a sacrificial wafer. A carrier wafer has a dielectric layer on a top surface which includes a layer of glass. The sacrificial wafer, after being subject to diffusion of highly doped semiconductor material, exhibits a plurality of varying depth regions. These regions manifest the basic transducer structure. By utilizing selective etching, one can thus form a transducer structure on the sacrificial wafer which is bonded to the carrier wafer by mean of an electrostatic bond. The resultant method and structure enables one to provide transducers with improved operating characteristics which are adaptable for many different modes of operation.

Abstract: A semiconductor transducer structure is fabricated by utilizing varying height diffused layers in a sacrificial wafer. A carrier wafer has a dielectric layer on a top surface which includes a layer of glass. The sacarificial wafer, after beign subject to diffusion of highly doped semiconductor material, exhibits a plurality of varying depth regions. These regions manifest the basic transducer structure. By utilizing selective etching, one can thus form a transducer structure on the sacrificial wafer which is bonded to the carrier wafer by means of an electrostatic bond. The resultant method and structure enables one to provide transducers with improved operating characteristics which are adaptable for many different modes of operation.

Abstract: A glass header structure for a pressure transducer employs a cylindrical member fabricated from a borosilicate glass having a thermal expansion coefficient which matches silicon. The glass header has a central aperture which extends from the top to the bottom surface. Positioned about the central aperture are four smaller apertures located at 90 degree intervals and each containing an elongated terminal pin. The pins are of a nail head configuration with a flat top head of a larger diameter than the diameter of the apertures and of the main pin body. Affixed to the flat top surfaces of the terminal pins by means of ball bonding are wires which connect to the terminal areas of a semiconductor pressure transducer which is mounted over the central aperture of the header.

Abstract: A high temperature transducer consists of a first section having a base layer of monocrystalline silicon which layer is coated with an oxide. A thin layer of a high temperature glass is sputtered on the oxide layer of the base layer. A second section is formed by diffusing a wafer of N type silicon to form a p+ layer. The first and second sections are bonded together by an anodic bond where the p+ layer is secured to the glass layer to form a composite structure. The N type material is then removed and piezoresistive deivces are formed in the p+ layer. This structure provides a high temperature transducer which exhibits stable operating parameters over a wide operating range.

Abstract: There is disclosed apparatus and methods of fabricating a piezoresistive semiconductor structure for use in a transducer. According to one method, a layer of silicon dioxide is grown over the surface of a first semiconductor wafer which is designated as a carrier wafer. A layer of glas is then formed on the top surface of the carrier wafer over said layer of silicon dioxide. A second wafer has diffused therein a high conductivity semiconductor layer which is diffused on a top surface of a sacrificial semiconductor wafer. The first and second wafers are then bonded together by means of an electrostatic bond with the high conductivity layer of the sacrificial wafer facing the glass layer of the first wafer. After securing the wafers together, one may etch away the remaining portion of the sacrificial wafer to provide a high conductivity resistive layer which is secured to the glass layer of the first wafer and is patterned to form a resistive network using standard photolithographic making.

Abstract: There is disclosed a medical transducer apparatus which employs composite planar members each of which is fabricated from a highly insulative material. The members are positioned in congruency and a first member which may be a composite member has a diaphragm area located on the surface thereof to which a piezoresistive gage is bonded. The gage is surrounded by an aperture in another member to enable leads from the gage to be directed to an interconnection and circuit board also fabricated from an insulator material. The structure provides isolation to the patient in regard to the biasing source used for the gage array and also provides isolation based on external voltage which serves to protect the transducer during operation.

Abstract: A transducer structure is disclosed which comprises a single crystal semiconductor diaphragm dielectrically isolated by a layer of silicon dioxide from a single crystal gage configuration. The methods depicted employ high dose oxygen which is ion implanted into a monocrystalline wafer to form a buried layer of silicon dioxide with the top surface of the wafer being monocrystalline silicon. An additional layer of silicon is epitaxially grown on the top surface of the wafer to enable the etching or formation of a desired gage pattern.

Abstract: A pressure transducer employs a tubular glass structure of a "D" shaped cross section, with the arcuate section of the "D" shaped configuration being substantially thicker than the base section. A sensor array is positioned on the underside of the base section while a pressure conducting fluid is directed through the tubular member to provide deflection of the base to cause the sensor array to provide an output indicative of pressure variations in the fluid medium. The sensor array as positioned on the underside of the base is both electrically and mechanically isolated from the pressure conducting medium.

Abstract: A hybrid transducer employing a ceramic substrate having on a surface a suitable geometry for defining an active or clamped area, a semiconductor strain gage is positioned on said substrate within said active area and connections are made to said gage by conductors printed on said substrate by thick or thin film techniques. Thick film printing techniques or thin film deposition techniques are employed to print the conductors, terminal areas, compensating resistors and stop members.

Abstract: A bridge array employing piezoresistive sensors responsive to the longitudinal piezoresistive effect generally exhibits a positive nonlinearity over a pressure range, while a bridge array employing piezoresistive sensors employing the transverse piezoresistive effect exhibits a negative nonlinearity over the pressure range. A composite pressure transducer is provided by interconnecting a longitudinal and transverse bridge array in a common composite configuration. The resulting transducer exhibits linear operation over the pressure range due to the cancellation of said nonlinearities from the connected arrays.

Abstract: A transducer structure is disclosed which comprises a single crystal semiconductor diaphragm dielectrically isolated by a layer of silicon dioxide from a single crystal gage configuration. The methods depicted employ high dose oxygen which is ion implanted into a monocrystalline wafer to form a buried layer of silicon dioxide with the top surface of the wafer being monocrystalline silicon. An additional layer of silicon is epitaxially grown on the top of the wafer to enable the etching or formation of a desired gage pattern.