Abstract: A pressure transducer is provided with a housing member that attaches to a rigid and generally planar member, such as a ceramic circuit board. The legs of the housing member can pass through holes in the circuit board or, alternatively, can attach to edges thereof. The legs of the housing are provided with bails which have steps shaped to seize the circuit board after the legs are flexed to permit insertion of the board between them. The housing is provided with an opening that is shaped to receive a media seal, a pressure sensor die and a conductive seal between a surface of the opening and a surface of the ceramic circuit board. When the circuit board is attached to the housing, the seals and the pressure sensor die are compressed therebetween to provide good fluid sealing association between the components and to also provide electrical communication between components on the pressure sensor die and components on the circuit board.

Abstract: A resistive pressure transducer wherein a flexible diaphragm is mounted in a spaced apart relationship to the upper surface of a base member. A conductive path is deposited on one surface of the diaphragm. A resistive configuration is also deposited on the same surface of the diaphragm. The resistive configuration includes four separate resistive patterns. The first and third resistive patterns are deposited in close proximity to the outer edge of the diaphragm. The first and third resistive patterns are each comprised of three radially extending resistors, spaced apart along the periphery of the diaphragm, and interconnected by conductive material. The second and fourth resistive patterns are deposited in close proximity to the center of the diaphragm. The first and third resistive patterns measure radial strain, while the second and fourth resistive patterns measure tangential strain. The four resistive patterns each forms a separate leg of a Wheatstone bridge configuration.

Abstract: A semiconductor sensor (10) is built into a cable connector to provide rapid and reliable attachment of the semiconductor sensor (10) into a monitoring or control system. The sensor (10) is mounted in a package (11) having cable connector leads (12, 13, 14) extending through the package (11). The semiconductor sensor (10) is electrically attached to the cable connector leads (12, 13, 14). A housing (20,30) surrounds the package (11) and provides a protective shroud for the cable connector leads (12, 13, 14).

Abstract: In a semiconductor sensor having double diaphragm structure, in which pressure to be measured is applied to diaphragm portions having distortion gages via a liquid filled in spaces partitioned by sealed diaphragms, as circuit elements of a signal processing circuit for processing an output of a distortion gage bridge are integrated in and on a semiconductor chip having diaphragm portions, the number of component parts used is reduced, and a compact size, a low cost, and high reliability are attained. This arrangement can be applied to any of the pressure sensors for detecting absolute pressure, relative pressure, and differential pressure.

Abstract: A low range pressure sensor includes a base plate of brittle material, and a diaphragm plate mounted on the base plate and sealed around a periphery to the base plate. Pressures are introduced to cause the diaphragm to deflect toward the base plate, and the deflection of the diaphragm is sensed through strain gauges to provide an indication of the pressure. The diaphragm is provided with a plurality of individual support posts on a side facing the base plate, so that when the diaphragm is deflected toward the base plate under high overpressures the support posts will support the diaphragm against movement to avoid failure or breakage of the diaphragm. The number of support posts can be varied as desired.

Abstract: A pressure sensor is provided with a means for efficiently removing heat from a circuit portion of a sensor die by providing an elastomeric member between a first surface of the sensor die and electrical leads. A thermally conductive, but electrically insulative, portion of the elastomeric member is disposed between the circuit portion of the sensor die and the leads and a means is provided for urging the first surface of the sensor die into thermal communicating contact with the thermally conductive portion of the elastomeric member. In addition, a selectively conductive portion of the elastomeric member is disposed between contact pads on the first surface of the sensor die and electrical leads encapsulated within a portion of the sensor housing. The elastomeric member is also provided with an opening formed therethrough and aligned with the diaphragm portion of the sensor die to permit the media to be in fluid communication with the diaphragm of the sensor die.

Abstract: A pressure sensing transmitter is provided that has high overpressure protection. The transmitter includes an housing having a first cell, a second cell, a sensing chamber, first and second pressure signal receiving means, and a differential sensor chip for measuring the pressure differential between the first and second pressure signal receiving means. Each cell further includes a cylinder with a clearance of an overpressure diaphragm mounted on the housing, an isolation diaphragm mounted on the other face, and a channel coupling the overpressure and isolation diaphragm and further coupling one cell to the first pressure signal receiving means and the other cell to the second pressure signal receiving means. Each overpressure diaphragm is positioned such that an overpressure protection cavity is formed between it and the housing. The first cell cavity is further coupled to the second pressure signal receiving means and the second cell cavity is further coupled to the first pressure signal receiving means.

Abstract: A resistive strain gauge pressure sensor including upper and lower housings coacting to define a pressure chamber within the housing. A board member assembly is clamped between the housings and defines a diaphragm portion which extends across the pressure chamber to divide the pressure chamber into upper and lower chamber portions. The board member assembly includes a relatively thin plate member, including a diaphragm portion, and a relatively thick support member bonded to the upper face of the thin plate member and including an annular portion positioned in surrounding relation to the diaphragm portion. The circuitry of the sensor is screen printed onto the lower face of the plate member and includes the various resistor elements of the strain gauge assembly, the various elements of the conditioning circuit receiving the output of the strain gauge assembly, and the various further leads required to connect the circuitry elements to the terminals of the sensor.

Abstract: Low temperature wafer bonding process enhancement makes a wafer surface hydrophobic, preparing it with a buffered oxide etchant and then exposing it to H.sub.2 O.sub.2 before thermoelectric bonding. Has particular application to diaphragm-based pressure sensor construction.

Abstract: A resistive strain gauge sensor of the type including a circuit board carrying circuitry, a diaphragm bonded to the circuit board, and strain gauge circuitry on the diaphragm. The strain gauge circuitry includes a plurality of leads defining free ends and the circuitry on the circuit board defines a plurality of leads defining free ends. The diaphragm is bonded to the circuit board by a frit layer and the frit layer includes voids which are in respective alignment with the free ends of the strain gauge leads and the free ends of the circuit board leads. A conductive epoxy is positioned in the voids in the frit layer to establish electrical communication between the strain gauge circuitry leads and the circuit board leads without the use of solder joints.

Abstract: A resistive strain gauge pressure sensor including upper and lower housings coacting to define a pressure chamber within the housing. A board member is clamped between the housings and defines a diaphragm portion which extends across the pressure chamber to divide the pressure chamber into upper and lower chamber portions. All of the circuitry of the sensor is screen printed onto the lower planar face of the board member including the various resistor elements of the strain gauge assembly, the various elements of the conditioning circuit receiving the output of the strain gauge assembly, and the various further leads required to connect the circuitry elements to the terminals of the sensor. The sensor terminals are provided by a plurality of connector pins extending downwardly through the board member for connection at their respective lower ends to the circuitry provided on the lower face of the board member.

Abstract: A pressure sensor for detecting pressure in a combustion chamber of internal combustion engines has a housing, a sensor element composed of a piezoresistive material and arranged in the housing, a diaphragm, a punch introducing a pressure to be determined onto the sensor element and located between the diaphragm and the sensor element. The punch has a counterbearing, a hybrid has a base, and a preprocessing circuit has electronic components. The sensor element, the hybrid with its base and the electronic components of the preprocessing circuit are located on the counterbearing of the punch.

Abstract: A pressure transducer employing at least one piezoresistive sensor fabricated from diamond. The diamond piezoresistive sensors are formed on a dielectric layer fabricated from silicon dioxide. The dielectric layer is formed on a silicon carbide force collector. In addition, the silicon carbide force collector may be fabricated from .alpha.-silicon carbide or p-type silicon carbide.

Abstract: A resistive strain gauge pressure sensor including upper and lower housings coacting to define a pressure chamber within the housing A board member is clamped between the housings and defines a diaphragm portion which extends across the pressure chamber to divide the pressure chamber into upper and lower chamber portions. All of the circuitry of the sensor is screen printed onto the lower planar face of the board member including the various resistor elements of the strain gauge assembly, the various elements of the conditioning circuit receiving the output of the strain gauge assembly, and the various further leads required to connect the circuitry elements to the terminals of the sensor. The sensor terminals are provided by a plurality of connector pins extending downwardly through the board member for connection at their respective lower ends to the circuitry provided on the lower face of the board member.

Abstract: An electrical circuit containing novel piezoresistive sensor is disclosed. The sensor is connected to a source of direct current, and a manometric pressure of at least about 15 p.s.i.g. is applied to the sensor.

Abstract: A semiconductor pressure sensor according to the present invention comprises a semiconductor substrate having a first surface, a second surface opposite to the first surface and a recess formed in the first surface, the recess defining an interior surface including a bottom surface; and a diffusion region extending from the adjacency of the bottom surface to the second surface. A pressure-sensitive resistance of the semiconductor pressure sensor is formed in the vicinity of the bottom surface of a diaphragm. Therefore, the pressure-sensitive resistance can be formed so as to be brought into alignment with the position of the diaphragm after the formation of the diaphragm. Accordingly, a semiconductor pressure sensor, which does not cause a displacement in position between the diaphragm and the pressure-sensitive resistance and is excellent in accuracy, can be easily fabricated.

Abstract: The formation of diaphragms by silicon wafer bonding provides for a structure having at least two such diaphragms with cavities in the wafers to which the diaphragm layer is bonded. Passageways through the wafers provide for communication of a fluid to the diaphragms. In some locations less than all of a plurality of diaphragms may be bonded to only one wafter having a cavity adjacent the diaphragm.

Abstract: A semiconductor pressure sensor according to the invention comprises a first semiconductor substrate and a second semiconductor substrate, disposed around the first substrate, so that signals obtained by the semiconductor pressure sensor under static or differential pressure conditions can be properly corrected and both static and differential pressures can be detected accurately and reliably measured on the same semiconductor substrates. Another object of the invention is provide a semiconductor pressure sensor which utilizes a single substrate with an aperture, which acts as a pressure overload stop mechanism, and which does not suffer from any effects of diaphragm deformation as a result of possible pressure overload.

Abstract: A semiconductor pressure sensor comprises a silicon substrate having a surface orientation of substantially (110), a diaphragm formed from the substrate, strain gauges disposed on the diaphragm, and a base joined with the substrate. The diaphragm has an octagonal shape whose sides are orthogonal to axis<100>, <110>, and<111>, respectively. This sensor causes substantially no output error and no fluctuation between output characteristics of the strain gauges irrespective of a change in temperature.

Abstract: A pressure sensor sub-assembly (18) has a solid-state sensing element (22) mounted on a laminated ceramic substrate (20) and has the electrical signal contacts (22a) on the sensing element electrically connected to connector pins (24) on the substrate. A manufacturing process can fabricate a batch of sub-assemblies on a substrate structure that is sub-divided to form the separate sub-assemblies. The sensor sub-assemblies can be tested, and graded, before or after the sub-division step, and then each mounted in a housing.

Abstract: A semiconductor pressure sensor includes a semiconductor pressure-sensing chip including a semiconductor body having a diaphragm that flexes in response to applied pressure, a strain gauge disposed in the diaphragm for altering an electrical signal in response to flexing of the diaphragm, and an amplifying circuit disposed in the semiconductor body outside the diaphragm and connected to the strain gauge for amplifying the electrical signal; a base supporting the semiconductor pressure-sensing chip; a package enclosing the semiconductor pressure-sensing chip and the base and having an opening providing access to the pressure-sensing chip; a plurality of leads penetrating the package and connected to the amplifying circuit; a substrate on which the package is mounted; and a gain-adjusting resistor disposed on the substrate opposite the package and electrically connected to the amplifying circuit for adjusting the gain of the amplifying circuit.

Abstract: In an integrated multisensor used in a differential and static pressure transmitter, a pair of static pressure gages are formed on a static pressure detecting diaphragm and another pair of static pressure gages are formed at positions on a fixed portion which are near to the center of a differential pressure detecting diaphragm. The second term generated by a differential pressure appearing in a static pressure sensor is a function of a distance. Therefore, equal influence is exerted on each static pressure gage. Accordingly, by constructing a static pressure sensor so as to form a bridge circuit, a static pressure value free of the influence of a differential pressure can be detected, thereby making it possible to determine an accurate differential and static pressure.

Abstract: There is provided a pressure measuring sensor having a diaphragm including a peripheral fixing portion so formed as to be fixed to a pressure measuring sensor proper and be thick, a pressure receiving portion responsive to a pressure to be measured to move, and a strain causing portion responsive to the movement of the pressure receiving portion to cause strain, the pressure receiving portion having a shape so formed as to substantially perform the same function as a member having a high rigidity when moving in response to a change in the above described pressure to be measured, and the strain causing portion being substantially subject to bending stress in response to the movement of the pressure receiving portion moved according to the change in the above described pressure to be measured and thereby the strain causing portion providing a plurality of gauge resistors formed on the strain causing portion with tensile stress or compressive stress proportionate to the pressure to be measured.

Abstract: A pressure transducer is provided which incorporates numerous stress reducing characteristics. A pressure sensor is mounted to a ceramic plate with a buffer plate there between to isolate the pressure sensor from stresses that could be transmitted through the ceramic plate. The ceramic plate is necessary for the purpose of supporting a plurality of electronic components which comprise an amplification and compensation circuit. The ceramic plate is separated from all parts of its housing except a minimal central surface on a support boss which provides the support for the pressure sensitive device. Electrical communication between conductive paths on the ceramic plate and terminals extending through the housing is provided by flexible electrical conductors. A cover is attached to the housing with snap acting contact which further isolate the housing from the cap.

Abstract: A pressure transducer apparatus for use with low voltage supply source. A semiconductor piezoresistive strain gauge bridge provides an analog output of pressure variations which includes errors introduced by variations in the ambient temperature. A non-temperature-sensitive resistor across the bridge input is used to decrease the temperature dependent voltage change necessary for temperature compensation of the strain gauge bridge circuit output. Analog temperature adjustment means, provide as an output a current whose value changes concurrently and in direct proportion to the change occurring in the strain gauge bridge circuit current. An analog to digital converter has as its analog input the voltage output of the strain gauge bridge circuit, which is integrated over a first time period, and has as its reference input the temperature-adjusted output current from the analog temperature adjustment means which is integrated over a second time period.

Abstract: A resistive strain gauge pressure sensor including upper and lower housings coacting to define a pressure chamber within the housing. A board member is clamped between the housings and defines a diaphragm portion which extends across the pressure chamber to divide the pressure chamber into upper and lower chamber portions. All of the circuitry of the sensor is screen printed onto the lower planar face of the board member including the various resistor elements of the strain gauge assembly, the various elements of the conditioning circuit receiving the output of the strain gauge assembly, and the various further leads required to connect the circuitry elements to the terminals of the sensor. The sensor terminals are provided by a plurality of connector pins extending downwardly through the board member for connection at their respective lower ends to the circuitry provided on the lower face of the board member.

Abstract: An overpressure-protected, differential pressure sensor (37) is formed by depositing diaphragm material (24) over a cavity (23) formed and filled with sacrificial material (22) into a front surface of a substrate. The sacrificial material (22) is then removed to create a free diaphragm. The floor of the cavity (23) defines a first pressure stop to limit the deflection of the diaphragm in response to pressure applied to the top of the diaphragm. A port (33) is created to allow pressure to be applied to the bottom side of the diaphragm (24). An optional second pressure stop, which limits the deflection of the diaphragm in response to pressure applied to the bottom side of the diaphragm, is formed by bonding a cap (35) to standoffs (34) placed around the top of the diaphragm. The standoffs are spaced to allow pressure to be applied to the top of the diaphragm.

Abstract: A force transducer usable tokodynamometer for measuring intrauterine pressure and motion, and for measuring other force exerted by human body or other organisms. The tokodynamometer has a cavity filled with an incompressible fluid and closed by a flexible diaphragm disposed for contacting the body portion being studied. A zero-displacement fluid-pressure transducer is in the cavity and provides an electrical signal responsive to pressure in the fluid, as body force acts through the flexible diaphragm to induce pressure in the fluid. Changes in intrauterine pressure or other body forces are thus measured with no significant physical displacement of a transducer or other force-measuring element. The fluid-filled cavity has the shape of a truncated cone with the diaphragm at the larger end and the transducer at the smaller end, increasing the sensitivity of the transducer.

Abstract: A pressure sensor having a ceramic support, a first ceramic layer attached to a peripheral portion of one side of the ceramic support, and a second ceramic layer which is attached to a peripheral portion of another side of the ceramic support such that the pressure sensor is shaped as an integral assembly. The ratio of the thickness of the first ceramic layer to that of the second ceramic layer is in the range of 1:10 to 1:1. The ratio of the thicknesses of the first and second ceramic layers to thickness of the ceramic support is no more than 1:2. The pressure sensor further includes a hollow space formed between the ceramic support and at least one of the first and second ceramic layers so that, after shaping as an integral assembly, the ceramic layer or layers will work as a diaphragm that is capable of deformation under pressure.

Abstract: A pressure sensor Comprising a disk-type base part having a preferably central opening spanned at one end by a surface-type pressure transducer, a pressure receiving part having a diaphragm arranged at distance from the other end side of said opening and integrally formed with a rigid ring having the same peripheral dimensions as the disk-type base part and being connected thereto. A distance holder is provided between the diaphragm and the pressure transducer fully transmitting any deformation of the diaphragm to the pressure transducer. Such a pressure transducer may be manufactured by a simple and cost-effective procedure with the various elements formed of ceramic, sintered and combined.

Abstract: A semiconductor pressure-detecting apparatus includes a semiconductor chip having a diaphragm and a frame molded within a resin with the diaphragm exposed. A reference pressure chamber may be provided between the diaphragm and the frame. Since the diaphragm is exposed, a medium, the pressure of which is to be measured, easily contacts the diaphragm. Therefore, if the stem is connected to a case containing the medium, a high pressure can be measured.

Abstract: A pressure sensor assembly is provided containing a substrate having signal conditioning circuitry disposed on both surfaces of the substrate, with the critical pressure sensing element disposed on one surface of the substrate and the laser trimmable resistors disposed on the other surface of the substrate. The preferred ported housing of this invention seals the one side of the substrate containing the pressure sensing element thereby forming a pressurizable chamber, while allowing the signal conditioning circuitry and resistors on the other surface exposed for calibration by laser trimming of the resistors. This eliminates the requirement for a separate housing for the critical pressure sensing element. In addition, when the preferred ported housing is mounted to the pressure sensing side of the substrate for formation of the sealed pressure chamber, the through-holes which electrically interconnect the signal processing circuitry on both sides of the substrate are also concurrently sealed.

Abstract: A semiconductor pressure sensor is manufactured by integrally encapsulating a semiconductor pressure, sensor chip, a pedestal, leads, wires and a die pad in an outer package except for the surface of a diaphragm of the semiconductor pressure sensor chip and the reverse side of the die pad. The ratio of the thickness of the pedestal to the thickness of the semiconductor pressure sensor chip is 7.5 or less, while the ratio of the diameter of an opening formed in the outer package at the surface of the diaphragm and the diameter of the diaphragm is 1 or more. The thermal stress generated in the semiconductor pressure sensor chip can freely be reduced to a desired value, and a semiconductor pressure sensor exhibiting a desired accuracy can therefore be obtained. Furthermore, since the semiconductor pressure sensor can be manufactured by an ordinary IC manufacturing process, a semiconductor pressure sensor with reduced cost and having high quality can be produced.

Abstract: A pressure sensor including a semiconductor strain gauge and resistors for compensating temperature, a zero point or the like and made of the same material as that of said semiconductor strain gauge are formed on a metal diaphragm thereof. The resistors for the compensating circuit and the strain gauge are simultaneously formed by patterning a polycrystalline silicone thin film or the like laminated on the diaphragm. As a result, the number of the elements and the manufacturing processes such as a soldering process are reduced for the purpose of improving manufacturing yield. In order to widen the zero point compensating range, a plurality of zero-point compensating resistors, if formed, are disposed on a circumference relative to the center of the diaphragm so as to reduced the scattering in the level of the resistance of each of the resistors.

Abstract: A monolithic pressure and/or temperature transducer comprises at least two sensitive semiconductor layers of III-V material sensitive to pressure and to temperature and supported by a common substrate of III-V material, which two layers comprise: a first layer doped with donor type impurities at a first concentration and having a first resistivity as a function of pressure and of temperature; and a second layer doped with donor type impurities at a second concentration different from the first concentration and having a second resistivity as a function of pressure and of temperature, which second resistivity depends on temperature in a different manner than the first resistivity.

Abstract: A pressure transducer circuit is provided which includes a bridge arrangement of piezoresistors which are connected to a diaphragm that is sensitive to a pressure which is monitored. The output of the sensor bridge is provided to a preamplifier which is, in turn, associated with an attenuation network and compensation circuitry. The transducer incorporates a plurality of temperature sensitive resistors within the compensation circuit and these temperature sensitive resistors are produced at the same time and during the same manufacturing step as the piezoresistors of the bridge arrangement. In addition, they are produced using the same dopant and are implanted or diffused in the same semiconductor layer as the piezoresistors. The pressure transducer circuit incorporates a plurality of trimmable resistors which are adjusted during a calibration stage to compensate for temperature variations and nonlinearity of the numerous components in the circuit.

Abstract: A transducer having a plurality of sensing elements disposed in a single diaphragm wherein each of the sensing elements is spaced from every other of the sensing elements a predetermined distance so as to control interference among the sensing elements. Each of the sensing elements preferably comprises a plurality of piezoresistors each of which are coupled in a Wheatstone bridge configuration. This transducer achieves sensitive, accurate, high spatial resolution measurements of non-uniform pressures.

Abstract: A low cost piezoresistive pressure transducer utilizing premolded elastomeric seals in which at least one seal is electrically conductive. A piezoresistive stress sensitive element in the form of a diaphragm of semiconductor material having a thickened rim is held at its rim between a pair of premolded elastomeric seals in a two piece housing. Electrical connections with external circuitry are made by conductive paths through one of the elastomeric seals which makes contact with electrical leads which pass through the housing wall.

Abstract: A silicon pressure sensor chip has a shear element on a sculptured diaphragm. The shear element is a piezo-resistive four-terminal resistor which is oriented so as to respond to the in-plane shear stress component in the diaphragm. The shear element is located on a thick shelf which is a portion of the sculptured diaphragm, which also has a thinner portion. This diaphragm configuration increases the bending moment at the location of the sensing element through the load of the thin portion of the diaphragm, which is suspended along the periphery of the thick shelf.

Abstract: A resistive strain gauge pressure sensor including upper and lower housings coacting to define a pressure chamber within the housing. A board member is clamped between the housings and defines a diaphragm portion which extends across the pressure chamber to divide the pressure chamber into upper and lower chamber portions. All of the circuitry of the sensor is screen printed onto the lower planar face of the board member including the various resistor elements of the strain gauge assembly, the various elements of the conditioning circuit receiving the output of the strain gauge assembly, and the various further leads required to connect the circuitry elements to the terminals of the sensor. The sensor terminals are provided by a plurality of connector pins extending downwardly through the board member for connection at their respective lower ends to the circuitry provided on the lower face of the board member.

Abstract: A structure and method of making a piezoresistive transducer with reduced offset current. The transducer is comprised of a piezoresistive die having a support rim and a diaphragm, and a support housing having a wall and an aperture. The shape of the diaphragm is matched with the shape of the aperture while the shape of the support rim is matched with the shape of the wall. By matching these shapes, temperature induced stresses are reduced, thus reducing temperature induced offset currents.

Abstract: A semiconductor pressure sensor comprising a diaphragm area formed on a semiconductor chip, a plurality of gauge resistances arranged on one face of the diaphragm area to form a bridge circuit, and an oxide film formed on the top of the diaphragm area, wherein at least one additional pattern is formed in a portion of said diaphragm area other than said gauge resistances. The thickness of the oxide film on said additional pattern is smaller than the thickness of the oxide film on portions other than said gauge resistances and said additional pattern.

Abstract: This invention provides a semiconductor film pressure sensor in which the pressure-sensitive resistance layers are made of an n-type polycrystalline silicon layer, and a method of manufacturing the sensor. In the semiconductor film pressure sensor of the invention, the pressure-sensitive resistance layers are formed on a diaphragm, and in addition a coarsely adjusting pattern and a finely adjusting pattern for zero point adjustment and the resistors of a temperature compensating circuit are formed on the diaphragm using the same n-type polycrystalline silicone layer. In formation of the n-type polycrystalline silicone layer, the substrate temperature is held at 500.degree. to 600.degree. C. The coarsely adjusting pattern and finely adjusting pattern for zero point adjustment, and the resistors of the temperature compensating circuit are formed in the same step as the pressure-sensitive resistance layers.

Abstract: A semiconductor pressure sensor comprises a diaphragm formed by anisotropic etching of silicon single crystal, characterized in that an etch-stop layer is provided at the site where etching is to be stopped, and that an etch-stop layer having insulating property is provided as the insulating layer of the pressure-sensitive portion.

Abstract: There is disclosed an apparatus and structure for a pressure transducer employing silicon carbide and utilizing p-type SiC as a diaphragm with n-type mesa SiC force sensing resistors integrally formed on the surface of the diaphragm. The p-type SiC diaphragm is positioned on top of an annular ring of silicon which is formed from a silicon wafer utilized as the supporting wafer for the process. The structure depicted is a given conductivity SiC diaphragm having opposite conductivity SiC resistors positioned thereon and fabricated by processing techniques utilizing selective etching properties of SiC.

Abstract: A semiconductor pressure sensor having a diaphragm formed over the surface of a semiconductor substrate by thin film forming technique is provided.

Abstract: A pressure transducer having means for improving the linearity and sensitivity of an output signal from the pressure transducer. Ribs and bosses are introduced in the diaphragm region to collect the moments caused by a difference in pressure on the two sides of the diaphragm and thus improve device sensitivity. In addition, the ribs and bosses prevent stretching of the piezoresistors thus improving the linearity of the device. A constraint can also be included to improve the alignment of the piezoresistors thus improving the linearity of the device.

Abstract: An apparatus and method for compensating for temperature dependent offset and fixed offset in a resistance bridge is disclosed. The apparatus comprises a resistance bridge, a compensation network and an instrumentation amplifier. The uncompensated output of the bridge is applied to the input of the instrumentation amplifier. The output of the compensation network is fed into the instrumentation amplifier to compensate for the temperature and offset dependent components of the bridge output. The output and resistance of the bridge are measured under conditions of constant pressure and temperature for different temperatures and pressures and the temperature coefficient of resistance, temperature coefficient of offset and temperature coefficient of sensitivity are calculated. These coefficients are used to select compensation network resistors.

Abstract: A pressure sensor has a thin plate diaphragm having a strain detecting section thereon, and a support member for receiving and properly positioning the diaphragm within a stepped bore structure. The pressure sensor with which the strain detecting section is formed on the diaphragm surface is formed by the use of semiconductor manufacture technology by making the diaphragm of the pressure sensor in the form of a thin plate member. The diaphragm and the support member are joined together by diffusion bonding, and heat treatment for this diffusion bonding is also utilized to crystallize the semiconductor strain gauges.

Abstract: The apparatus for sensing pressure comprises a header, having at least one input port for receiving a substance under pressure. A substrate, having a wafer-like shape with a relatively large surface area in comparision to its thickness, includes at least one internal passage to couple the substance under pressure. A pressure sensing element is mounted onto the surface of the substrate over an exit port of the internal passage coupling the substance under pressure. The substrate is bonded to a surface of the header at extreme locations from a location in which the pressure sensing element is mounted. Thus isolation is provided for the pressure sensing element from unwanted stresses induced in the substrate.