Abstract: A moat having a flat bottom and tapered side walls is formed in a monocrystalline silicon body (substrate) and extends from a top surface of the substrate into the substrate. An oxide layer is grown over side walls and a bottom of the moat and then is selectively removed from the bottom of the moat to expose silicon. An epitaxial stalk (a recessed mesa) is grown on the silicon at the bottom of the moat to a height which makes its top at least coplanar with the top surface of the substrate.

Abstract: A moisture sensor consists of an array of spaced apart, highly abrasion-resistant electrodes disposed on the outside surface of the windshield of a vehicle. When moisture is present, the spaces between the electrodes are bridged by the water and the output impedance of the sensor significantly decreases. This signals the presence of moisture. The electrodes have particles of a conductive metal oxide, e.g., ruthenium oxide, dispersed with a glass matrix which is fused to the windshield glass. The electrodes are formulated as an ink including particles of the metal oxide, a glass frit, and an organic binder. The ink is silk screened onto the windshield in the desired electrode pattern. After drying of the ink, the glass frit is fused to the windshield during normal heating of the windshield to shape it in a known windshield shaping (sagging) process. Novel two layer sensor arrangements, providing even greater resistance to abrasion, are also described.

Abstract: A printed circuit board assembly uses a conductive pattern that includes both firmly adherent conductors and controllably adherent conductors. The controllably adhering conductors are free to lift off the printed circuit board to relieve mechanical forces caused by thermal stresses at solder joints between the controllably adherent conductors and integrated circuit chips of the assembly.

Abstract: A driver circuit, which uses two serially connected enhancement mode n-channel MOS transistors in which the pullup transistor of the two transistors has no p-type implant in the channel region thereof and the pulldown transistor of the pair is a normlal enhancement mode transistor having a p-type threshold control implant in the channel thereof, is useful as a driver circuit for CMOS circiuts. The pullup transistor is designed to have a threshold of about 0 volts at zero back gate bias and the pulldown transistor is designed to have a threshold voltage of about 0.7 volts at zero back gate bias.

Abstract: A method for preferentially etching phosphosilicate glass to form a micromechanical structure includes forming a layer of phosphosilicate glass on a substrate and opening at least one via in the phosphosilicate glass layer. A layer of material which is patterned to produce a micromechanical structure is formed over the phosphosilicate glass layer which extends through the via and adheres to the substrate. The phosphosilicate glass layer is then removed by immersing the device in an etchant bath containing an aqueous ammoniacal hydrogen peroxide solution. The resulting micromechanical structure has at least one point of attachment to the substrate and is otherwise spaced apart from the substrate by an air gap. A method for attaching an overhanging mass to a miniature cantilever beam using microelectronics fabrication technology is also provided in which the center of gravity is shifted to the endpoint of the free end of the beam.

Abstract: A pressure sensor uses a monocrystalline silicon chip that has a diaphragm portion in which strain gages are formed that overlie a buried cavity. The cavity is formed by a single sided semiconductor fabrication process that includes a pair of preferential etching steps and an epitaxial deposition step.

Abstract: In the fabrication of various hybrid devices, it is the practice to provide thick film conductors of two different compositions, namely, a high palladium content silver-palladium film and an essentially pure silver film. The silver-palladium films are used because of their excellent physical and chemical properties, but are relatively expensive. The silver-based films do not have comparably good properties (with the exception of low electrical resistivity), but are less expensive than the silver-palladium films and are used in substitution therefore on less "demanding" areas of the device. However, the two films interact when in contact, and discontinuities or open circuits can occur as a result. The present invention provides a novel silver-based conductor film including a small percentage of palladium and one or both of aluminum oxide and silicon dioxide.

Abstract: For increased sensitivity, an improved position sensor includes a magnetic circuit in which the stationary portion includes a permanent magnet whose width is optimally 1.5 times the tooth pitch of the exciter portion of the sensor and the magnet face proximate the exciter includes a thin layer of ferromagnetic material over which is centered a narrow magnetic sensing element, such as a magnetoresistor. The sensing element has a width typically less than the tooth width. The sensing element includes a thin film of a monocrystalline semiconductive material, preferably having only a moderate bulk mobility and a larger band gap, such as indium arsenide. Current carriers flow along the length of the thin film in a surface accumulation layer, effective to provide a significant apparent increase in mobility and conductivity of said semiconductive material, and an actual increase in magnetic sensitivity and temperature insensitivity.

Abstract: A magnetoresistive sensor that includes a thin film of nominally undoped monocrystalline indium arsenide. An indium arsenide film is described that appears to have a naturally occurring accumulation layer adjacent its outer surface. With film thickneses below 5 micrometers, preferably below 3 micrometers, the presence of the accumulation layer can have a very noticeable effect. A method for making the sensor is also described. The unexpected improvement provides a significant apparent increase in mobility and conductivity of the indium arsenide, and an actual increase in magnetic sensitivity and temperature insensitivity.

Abstract: For increased sensitivity a position sensor includes a magnetic circuit in which the stationary portion includes a permanent magnet whose width is optimally 1.5 times the tooth pitch of the exciter portion of the sensor and the magnet face proximate the exciter includes a thin layer of ferromagnetic material over which is centered a narrow magnetic sensing element, such as a magnetoresistor. The sensing element has a width typically less than the tooth width which is between 0.17 and 0.37 the tooth pitch. The needed flux density is typically available simply by appropriate magnet thickness or choice of magnet material without the need of a flux guide.

Abstract: A magnetodiode for use in a magnetic sensor using a semiconductive element (advantageously of a direct band-gap, high mobility material such as gallium arsenide) that has a superlattice formed by an n-i-p-i doping profile or superstructure. Such a superlattice is used to provide a region of long recombination times for the normal flow of charge carriers from which the carriers are deflected into short recombination time regions by a magnetic field being sensed.

Abstract: Superconducting thin films of YBa.sub.2 Cu.sub.4 O.sub.7, having a superconducting transition temperature of 90.degree. K., are produced in a non-vacuum environment using Mettalo-Organic Deposition techniques. An ink comprising the neodecanoates of yttrium, barium, and copper is formed and spun on a single crystal substrate of strontium titanate. The ink is dried in an air environment, heated in an air environment at a temperature sufficient to decompose the neodecanoates, about 500.degree. C., and then heated again to promote recrystallization and grain growth of the remaining metal oxides. The resulting thin film exhibits superconductive characteristics at about 90.degree. K.

Abstract: A method for preferentially etching phosphosilicate glass to form a micromechanical structure includes forming a layer of phosphosilicate glass on a substrate and opening at least one via in the phosphosilicate glass layer. A layer of material which is patterned to produce a micromechanical structure is formed over the phosphosilicate glass layer which extends through the via and adheres to the substrate. The phosphosilicate glass layer is then removed by immersing the device in an etchant bath containing an aqueous ammoniacal hydrogen peroxide solution. The resulting micromechanical structure has at least one point of attachment to the substrate and is otherwise spaced apart from the substrate by an air gap. A method for attaching an overhanging mass to a miniature cantilever beam using microelectronics fabrication technology is also provided in which the center of gravity is shifted to the endpoint of the free end of the beam.

Abstract: A process is used to form in a common substrate a PMOS transistor of the lightly doped drain (LDD) type, an NMOS transistor of the LDD type and a vertical n-p-n bipolar transistor. In particular: the steps used to form an n-type well for the PMOS transistor, and an n-type drain extension well for the NMOS transistor, are also used to form the n-type collector of the bipolar transistor; the steps used to form the p-type extension well for the PMOS transistor are also used to form the p-type base of the bipolar transistor, the source/drain implantation step for the NMOS transistor is also used to form the emitter and a contact region for the collector of the bipolar transistor; and the source/drain implantation step for the PMOS transistor is used to form a contact region for the base of the bipolar transistor.

Abstract: A magnetic sensor is formed by a diode that includes a silicon element whose bulk is of high resistivity and low recombination velocity material and which includes spaced apart on its top surface n-type and p-type zones to which are provided electrical terminals. The element is treated to form at the top surface regions of high recombination velocity so located that when a voltage is applied between the electrical terminals to establish a flow of minority charge carriers between the p-type and n-type zones, such flow, in the absence of an applied magnetic field to be sensed, is little affected by the surface regions of high recombination velocity, but in the presence of any such field, is deflected into such surface regions and extinguished. Advantagously, the surface regions are formed by etching to form grooves and then ion implanting the grooved regions.

Abstract: Hot foil printing apparatus (10) for printing letters, etc. on a surface of a plastics substrate in which the surface of the plastics substrate is presented to a heated die (16) and a printing tape (24) is compressed between the surface of the plastics substrate and the heated die to print the letters on the plastics substrate, and in which the surface of the plastics substrate is heated by heating apparatus (42) before it is presented to the heated die. Provides improved print quality and quicker throughput.

Abstract: A monolithic pressure sensitive silicon integrated circuit is formed by first providing a localized etch-stop layer on one surface of the silicon chip, then growing successive epitaxial layers of opposite conductivity types over this surface. In the upper of the two layers, there is formed a bridge of four piezoresistors overlying the periphery of the etch-stop layer and the conditioning circuitry for amplifying the output of the bridge including both lateral and vertical junction transistors. The back surface of the chip is etched anisotropically to form a cavity that leaves a thin diaphragm underlying the bridge of the four piezoresistors.

Abstract: An integrated circuit device uses a silicon chip having an epitaxial layer which has two portions of different thicknesses in which are formed separate junction transistors of different characteristics. In the growth of the epitaxial layer there is first formed on the front surface of the chip a localized sacrificial silicon dioxide layer removable in situ by baking in a reducing atmosphere. Then an epitaxial layer is grown by a first epitaxial deposition phase selectively over only the silicon dioxide free regions of the front surface of the chip. The sacrificial silicon dioxide layer is then removed in situ by baking in hydrogen. There is then resumed blanket growth of the epitaxial layer by a second epitaxial deposition phase.

Abstract: A high temperature logic field effect transistor. By surrounding the source and drain pn junctions with electrically insulative material, except where a channel runs between the source and drain, a logic field effect transistor whose on/off current ratio can still have a high value at high temperatures. The transistor can be of any standard MOS technology, such as pMOS, nMOS, or CMOS.

Abstract: A semiconductor power device with bipolar regenerative switching characteristics provides insulated gate structures for controlling device turn-on and turn-off. Rapid turn-off is achieved in part by a lateral field effect pinch resistance and a vertical field effect pinch resistance produced by an electrically floating structure. The device is electrically isolated by layer of dielectric which allows it to be easily integrated with other circuit elements. The device can be controlled by low current and low positive voltages which provides for simpler interfacing and better electrical compatibility with other circuits in an automotive system. A method of manufactuing this device is also provided.