Abstract: A differential and absolute transducer are secured to a Pyrex glass header by means of a glass metal frit or other suitable interface. One of the sensors measures absolute pressure and the sensor is a sealed cavity, while the other sensor is designed to measure differential pressure and the sensor is an aperture which permits the pressure media to reach both sides of the sensor. The header itself has a through hole connected to a tube over which the differential sensor is affixed. The Pyrex glass is chosen to match the coefficient expansion of the sensors. The header in turn is attached to the tubular member provided with a fitting such that static pressure can be applied to both sensors simultaneously. At the other end of the tubular member, there is provided another fitting attached to the tube in the header through which the total pressure can be applied to the differential sensor, thus permitting the measurement of the difference between the total pressure and the static pressure.

Abstract: A hermetically sealed high temperature pressure transducer assembly including: a sensor wafer that includes a plurality of sensor structures and contact areas selectively interconnected and formed on a surface thereof is provided. A first header assembly coupled to the sensor wafer includes a plurality of pins, each of which are electrically coupled to an associated contact area. A second header assembly is coupled to the first assembly and to a sleeve, and includes a plurality of tubes into each of which one of the plurality of pins is positioned. A temperature insulated cable is partially positioned within the sleeve and includes a plurality of wires coupled to the pins. A third header apparatus is coupled to the sleeve and includes a plurality of closed-ended tubes for serving as leads, where each one of the plurality of wires is partially positioned in and coupled to a respective closed-end tube.

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 force transducer assembly for measuring compressive and tensile loads applied to a force transmission device, the assembly includes a housing, a sleeve assembly and a sensor device. The housing has a hollow interior. The sleeve assembly is coupled within the interior of the housing. The sensor device is secured within the interior of the housing between a portion of the sleeve assembly and a portion of the housing. The sensor device includes first and second sensors each including an isolation diaphragm at least partially defining an oil-filled cavity, and a piezoresistive sensor positioned so as to be effected by a change in pressure in the oil-filled cavity. When a first force is applied to the apparatus in a first direction via the force transmission device, one of the isolation diaphragms is deflectable in response thereto, and when a second force is applied in a second direction opposite to the first direction, the other of the isolation diaphragms is deflectable in response thereto.

Abstract: A method for making silicon-on-sapphire transducers including the steps of forming a first silicon layer on a first side of a first sapphire wafer; bonding a second sapphire wafer to the first side of the first sapphire wafer such that the first silicon layer is interposed between the first and second sapphire wafers; reducing the thickness of the first sapphire wafer to a predetermined thickness; depositing a second silicon layer on a second surface of the first sapphire wafer, wherein the second surface of the first sapphire wafer is oppositely disposed from the first surface of the first sapphire wafer; bonding a silicon wafer to the second surface of the first sapphire wafer such that the second silicon layer is interposed between the first sapphire wafer and the silicon wafer, wherein the silicon wafer includes p+ regions indicative of a transducer structure and non-p+ regions; and, removing the non-p+ regions of the silicon wafer thus forming the transducer structure of p+ regions on

Abstract: A method for measuring multiple pressures and a pressure sensing system for accomplishing the same. The method for measuring a plurality of pressures includes, exposing each of a plurality of pressure sensors to a corresponding plurality of environments each having a corresponding pressure to be measured, determining how frequently to measure each of the plurality of pressures, determining a sequence for utilizing the pressure sensors to measure the corresponding plurality of pressures, the sequence being dependent upon the determined frequency for each of the plurality of pressures and selectively utilizing each of the plurality of pressure sensors according to the determined sequence to measure the pressure to which it is exposed.

Abstract: A hermetically sealed high temperature pressure transducer assembly including: a sensor wafer that includes a plurality of sensor structures and contact areas selectively interconnected and formed on a surface thereof is provided. A first header assembly coupled to the sensor wafer includes a plurality of pins, each of which are electrically coupled to an associated contact area. A second header assembly is coupled to the first assembly and to a sleeve, and includes a plurality of tubes into each of which one of the plurality of pins is positioned. A temperature insulated cable is partially positioned within the sleeve and includes a plurality of wires coupled to the pins. A third header apparatus is coupled to the sleeve and includes a plurality of closed-ended tubes for serving as leads, where each one of the plurality of wires is partially positioned in and coupled to a respective closed-end tube.

Abstract: A differential pressure transducer comprising: a housing having a first end containing a first recess, and an oppositely disposed second end containing a second recess; first and second isolation diaphragms respectively enclosing said first and second recesses and forming in conjunction therewith first and second cavities; first and second headers secured within said housing and being electronically coupled together; and, a pressure sensor being adapted to withstand an excess in either said first or second pressures and secured to said first header so as to isolate said first and second cavities from one another and being responsive to a first pressure applied to said first diaphragm and a second pressure applied to said second diaphragm to produce at least one signal indicative of a difference between said first and second pressures.

Abstract: An improved method for making silicon-on-sapphire transducers including the steps of: forming a first silicon layer on a first side of a first sapphire wafer; bonding a second sapphire wafer to the first side of the first sapphire wafer such that the first silicon layer is interposed between the first and second sapphire wafers; reducing the thickness of the first sapphire wafer to a predetermined thickness; depositing a second silicon layer on a second surface of the first sapphire wafer, wherein the second surface of the first sapphire wafer is oppositely disposed from the first surface of the first sapphire wafer; bonding a silicon wafer to the second surface of the first sapphire wafer such that the second silicon layer is interposed between the first sapphire wafer and the silicon wafer, wherein the silicon wafer includes p+ regions indicative of a transducer structure and non-p+ regions; and, removing the non-p+ regions of the silicon wafer thus forming the transducer structure of p+

Abstract: A method for sealing a transducer of a type having a diaphragm with an active region and an inactive region, a stress sensing network associated with the active region of the diaphragm, contacts associated with the inactive region of the diaphragm, and lead-outs for coupling the stress sensing network to the contacts. The method comprises oxidizing the transducer to provide a first oxide layer which covers the diaphragm, the stress sensing network, the lead-outs and the contacts. Next, a layer of semiconductive material is deposited over the first oxide layer and is then planarized to provide a planar surface having a substantially flat and bondable surface. Finally, a cover member is bonded to the planar surface of the layer which covers the inactive region of the diaphragm to hermetically seal the stress sensing network and thereby provide a sealed transducer.

Abstract: A method for substantially improving the photoluminescent performance of a porous semiconductor, involving the steps of providing a bulk semiconductor substrate wafer of a given conductivity, wherein the substrate wafer has a porous semiconductor layer of the same conductivity as the bulk semiconductor substrate wafer, and the porous semiconductor layer is made up of a plurality of pores interspersed within a plurality of nanocrystallites, wherein each of the pores is defined by a pore wall and each of the nanocrystallites has a given thickness. Next, in the method, at least one monolayer layer of passivating material is generated on the pore wall of each of the pores, to passivate the porous semiconductor layer. The one layer of passivating material substantially eliminates dangling bonds and surface states which are associated with the porous semiconductor layer. The resulting passivated porous semiconductor layer exhibits a quantum efficiency of approximately 5 percent.

Abstract: There is disclosed a semiconductor sensor device comprising a semiconductor diaphragm member having a top surface coated with an oxide layer; P+ sensor elements fusion bonded to the oxide layer at a relatively central area of the diaphragm; P+ finger elements fusion bonded to the oxide layer extending from the sensors to an outer contact location of the diaphragm for each finger; and an external rim of P+ material fusion bonded to the oxide layer and surrounding the sensors and fingers. A first glass wafer member is electrostatically bonded at a bottom surface to the fingers and rim to hermetically seal the sensors and fingers of the diaphragm member.

Abstract: A multilayered LED structure which has an active light-emitting layer of porous silicon carbide and a sequence of layers of porous silicon carbide underneath which serves as a quarter-wavelength multilayer mirror. The result is the electroluminescent emission of spectrally narrow visible light in the deep blue to UV range, in a highly directed pattern. The deep, intense blue luminescence is accomplished via the appropriate preparation and passivation of a single porous silicon carbide layer, followed by the deposition of a transparent, semiconducting layer, such as ITO (In2O3) or ZnO.

Abstract: A method for selective conductivity etching of a silicon carbide (SiC) semiconductor includes forming a p-type SiC layer on a substrate layer, forming an n-type SiC layer on the p-type SiC layer, and photoelectrochemically etching selected portions of the n-type SiC layer by applying a bias voltage to the n-type SiC layer in a hydrofluoric acid (HF) solution while exposing the layer to a pattern of UV light. The bias potential is selected so that the n-type SiC layer will photo-corrode and the p-type SiC layer will be inert and act as an etch stop. The light pattern exposure of the n-type SiC layer may be done by applying a photolithographic mask to the layer, by projecting a collimated light beam through a patterned mask, or by scanning with a focused micrometer-sized laser beam on the semiconductor surface.

Abstract: A pressure transducer employing a metal isolation diaphragm. A volume of oil is located between the metal diaphragm and a silicon sensor received in a base member. In order to reduce errors at very low pressure caused by the oil exerting a tension on the deflecting portion of said silicon sensor, the metal diaphragm has an extending dome or dimple above the location of the silicon sensor. The silicon sensor is also recessed below the supporting base plate so that the separation between the silicon sensor and the metal diaphragm increases. The base plate also contains a series of shallow, narrow concentric grooves which further reduces surface tension between the metal diaphragm and the base plate.

Abstract: A semiconductor sensor device including a semiconductor diaphragm member having a top surface coated with an oxide layer; P+ sensor elements fusion bonded to the oxide layer at a relatively central area of the diaphragm; P+ finger elements fusion bonded to the oxide layer extending from the sensors to an outer contact location of the diaphragm for each finger; and an external rim of P+ material fusion bonded to the oxide layer and surrounding the sensors and fingers. A first glass wafer member is electrostatically bonded at a bottom surface to the fingers and rim to hermetically seal the sensors and fingers of the diaphragm member. The first glass wafer includes a depression above the sensors and has a plurality of apertures, where each aperture is associated with a separate finger at the contact location and each aperture being smaller than the associated finger lining up with the contact location wherein each contact location can be accessed via the associated aperture in the first glass wafer member.

Abstract: A hermetically sealed sensor device having a glass member defining a mounting surface and base surface, the glass member including one or more pin apertures extending through the glass member from the mounting surface to the base surface. A metallic pin is disposed in each of the pin apertures, each pin having a portion extending above the mounting surface. The sensor device also includes a semiconductor sensor chip including a semiconductor device and a cover hermetically bonded and sealed to a surface of the semiconductor device, the cover protecting the semiconductor device from the external environment. The is chip hermetically bonded and sealed to the mounting surface of glass member. The semiconductor device has one or more contacts disposed on the surface thereof, for making electrical contact thereto, the cover having one or more contact apertures extending therethrough which exposes a portion of the contacts.

Abstract: A multilayered LED structure which has an active light-emitting layer of porous silicon carbide and a sequence of layers of porous silicon carbide underneath which serves as a quarter-wavelength multilayer mirror. The result is the electroluminescent emission of spectrally narrow visible light in the deep blue to UV range, in a highly directed pattern. The deep, intense blue luminescence is accomplished via the appropriate preparation and passivation of a single porous silicon carbide layer, followed by the deposition of a transparent, semiconducting layer, such as ITO (In.sub.2 O.sub.3) or ZnO.

Abstract: A pressure sensor assembly including semiconductor transducer elements disposed upon a diaphragm support structure, wherein the support structure is comprised of a plurality of substrate layers anodically bonded together. A groove is disposed in the support structure creating an area of reduced thickness within the support structure. The ares of reduced thickness acts as a stress concentration region. As such, the transducer elements are disposed within the areas of reduced thickness so as to efficiently monitor any deformations experienced by the support structure. The groove that creates the areas of reduced thickness is formed in each of the substrate layers, prior to bonding into the overall structure, as such a very accurately tolerance groove can be formed into structure which greatly increases the reliability of the structure.

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.