Abstract: A high temperature pressure transducer employing dielectrically isolated beta silicon carbide pressure sensing elements situated on a diaphragm also fabricated from beta silicon carbide. The dielectrically isolated pressure sensing elements are formed on the diaphragm in method which employs two separately fabricated wafers that are later bonded together.

Abstract: A reduced size, hermetically sealed semiconductor transducer and methods for fabricating the same. In a preferred embodiment, the transducer comprises a transducer wafer including a diaphragm which deflects upon the application of a force thereto. At least one semiconductor transducer element and one electrical contact are disposed on a top surface of the transducer wafer, with the electrical contact coupled to the semiconductor element and extending to a peripheral portion of the wafer. A cover member is provided that is dimensioned to surround the semiconductor element. A peripheral glass frit bond is formed between the cover member and the transducer wafer, and between the cover member and at least a portion of the electrical contact. An aperture is formed in a top portion of the cover member, positioned above a region bounded by the peripheral glass bond. This aperture functions to prevent air gap formation in the peripheral glass frit bond.

Abstract: A pressure sensing device for producing an output proportional to an applied pressure irrespective of vibration and acceleration of the device, the device including: a first deflecting diaphragm formed in a first wafer and including a first plurality of piezoresistors mounted thereon, the first diaphragm being responsive to the applied pressure and vibration of the device; and, a second deflecting diaphragm formed in the first wafer and including a second plurality of piezoresistors mounted thereon, the second diaphragm being responsive only to vibration of the device; wherein, the first and second pluralities of piezoresistors are electrically coupled together to provide a common output such that they cooperatively at least partially cancel a portion of the common output associated with the vibration of the device.

Abstract: A single chip dielectrically isolated leadless pressure sensor adapted to substantially simultaneously measure a first pressure and a differential between the first pressure and a second pressure including: a wafer including first and second recessed portions respectively defining first and second deflectable diaphragms and at least one rim portion formed between the first and second recessed portions for isolating the first deflectable diaphragm from the second deflectable diaphragm; a first circuit mounted on the first deflectable diaphragm and being responsive to the first pressure; and a second circuit mounted on the second deflectable diaphragm and being responsive to the second pressure; wherein, the first and second circuits are adapted to be electrically coupled to one another so as to cooperatively provide a common output indicative of a differential pressure associated with the first and second pressures, while simultaneously partially providing an output indicative of the first or 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: An apparatus and method for making ultra high temperature silicon carbide pressure transducers which prevents the deterioration of contact areas under harsh conditions, such as high temperatures and oxidizing atmospheres includes a first substrate of silicon carbide with a plurality of piezoresistive elements disposed on a central active region. A plurality of generally L-shaped contact areas extend from and substantially surround the central active region. On each contact area a metalized contact is formed. An isolation moat etched around the periphery of the first substrate separates each contact area from the other, and separates the contact areas from the periphery of the device. A second substrate of silicon carbide having a plurality of apertures extending therethrough which align with and correspond to a contact on each contact area is joined to the first substrate by electrostatic bonding or by employing a glass frit.

Abstract: The present compensating circuit operates to reduce the span shift error due to ambient temperature changes of a span resistance compensated, bridge array circuit arrangement for a semiconductor transducer employing piezoresistive sensors. The span resistance method alone cannot reduce the span shift error to less than one percent (1%) for full scale. The present compensating circuit applies a constant voltage source, derived from the voltage source applied to the transducer, to a non-inverting input to an operational amplifier. The circuit also applies an ambient temperature dependent voltage, derived from the ambient temperature dependent bridge resistance of the bridge array circuit, to an inverting input of the operational amplifier. Both inputs to the operational amplifier are fed back through a different resistance loop to control the output voltage in response to the non-linearity of the ambient temperature dependent bridge resistance.

Abstract: A metal-oxide-semiconductor field-effect transistor (MOSFET) device comprising a carrier wafer and a silicon gate region disposed on the carrier wafer. A source region and a drain region made from 3C-silicon carbide are disposed on the carrier wafer above the gate region. A gate oxide, derived from silicon, separates the source and drain regions from the gate region. Laterally oriented oxide trenches separate and dielectrically isolate the MOSFET device from other devices on the carrier wafer. Further, the MOSFET device described above is manufactured in a method comprising the steps of providing a carrier wafer having an oxide layer formed on a surface thereof. A layer of silicon having a given level of conductivity is bonded to the oxide layer of the carrier wafer. Selected portions of the layer of silicon are oxidized to create a plurality of dielectrically isolated silicon islands, one of which forms a gate region.

Abstract: A field effect transistor device constructed in accordance with the present invention includes a channel of semiconductive material such as silicon having at least one row of pores extending therethrough. Internal pn junctions are fabricated within the porous region, such that the inside of each pore is coated with a layer of opposite conductivity type semiconductive material. When voltage is applied to the internal pn-junctions, the space charge around the pores widens or contracts, depending upon the direction of the bias, thereby permitting the modulation of current flow through the channel.

Abstract: A circuit for linearizing the output of a differential pressure transducer includes first and second operational amplifiers. Each amplifier is associated with threshold devices as diodes so that one amplifier will be active for one condition of output polarity while the other amplifier will be active for the other condition of output polarity. The output of the amplifiers are connected to a common terminal which provides a compensating biasing voltage to the transducer. The voltage varies in a "V" shaped characteristic to enable one to achieve a linear output voltage from the transducer for both positive and negative pressure differences.

Abstract: There is disclosed a semiconductor pressure transducer which employs a piezoresistive array fabricated on the surface of a thin substrate member and having the piezoresistors coupled to metallic contacts via ion implanted terminal leads.