Abstract: A semiconductor pressure sensor includes a SOI substrate composed of first and second silicon substrates. A diaphragm portion is formed by the first silicon substrate as a bottom of a recess portion formed in the second silicon substrate. Strain gauges are formed on the diaphragm portion, and a circuit portion is formed on the first silicon substrate at a region other than the diaphragm portion. ALOCOS film for isolating the strain gauges from the circuit portion is formed on the first silicon substrate outside the outermost peripheral portion of the diaphragm portion.

Abstract: A semiconductor pressure sensor has a recess formed on a semiconductor substrate. The recess has a sidewall, a bottom wall that serves as a diaphragm for detecting a pressure, and a corner portion provided between the sidewall and the bottom wall and having a radius of curvature R.

Abstract: A pressure detecting bridge circuit produces a sensor signal Sd. A temperature detecting bridge circuit produces a temperature signal St. A reference voltage generating circuit produces a reference signal Sa. An analog multiplexer processes these signals Sd, St and Sa in a time-divisional manner. A differential amplification circuit and an A/D conversion circuit are commonly used to obtain the digital data corresponding to the sensor signal Sd, the temperature signal St and the reference signal Sa. The temperature detecting bridge circuit includes reference resistance elements. By adjusting the design resistance values of the reference resistance elements, the variation width of the sensor signal Sd in a pressure measuring range of the pressure detecting bridge circuit is substantially equalized in advance with the variation width of the temperature signal St in a temperature measuring range of the temperature detecting bridge circuit.

Abstract: A light-receiving element having a light-receiving portion is formed on a chip surface. A digital circuit element, an analog circuit element and a circuit adjusting element are provided for cooperatively processing a detection signal produced from the light-receiving element. And, a light-shielding film is provided for selectively setting a light-receiving region on the chip surface.

Abstract: A pressure detecting apparatus has a single-crystal semiconductor sensor chip disposed on a metallic diaphragm through a low melting point glass. The sensor chip has a planar shape selected from a circular shape, a first polygonal shape having more than five sides and having interior angles all less than 180°, and a second polygonal shape having a ratio of a circumscribed circle diameter relative to an inscribed circle diameter being less than 1.2. Four strain gauge resistors are disposed on X, Y axes passing through a center point O of the sensor chip in parallel with <110> directions. Accordingly, thermal stress is reduced not to adversely affect a detection error and simultaneously high sensitivity is provided.

Abstract: In a sensor having a membrane structure, a sensor chip (silicon substrate) is provided with a through hole that is open on both upper and lower surfaces of the silicon substrate. A sensor element having a membrane structure is formed on the upper surface of the silicon substrate to close the through hole on the upper surface. The lower surface of the silicon substrate is bonded to a stem through adhesive to define a communication passage through which an inside and an outside of the through hole communicate with each other. Accordingly, the sensor can exhibit high reliability.

Abstract: A semiconductor acceleration sensor, which prevents an adhesion of a movable portion to a fixed portion due to an electrostatic force generated during being handled. The acceleration sensor has a sensor portion and a handling portion. The sensor portion has a first semiconductor layer; a movable portion including a weight portion supported to the first semiconductor layer for moving in accordance with an acceleration externally applied thereto and movable electrodes integrally formed with the weight portion; and fixed electrodes having a detection surface confronted to a detection surface of the movable electrodes and supported to the first semiconductor layer. The handling portion is to be contacted during being handled, and is provided at surrounding portion of the sensor portion with a trench interposed therebetween. The sensor portion is electrically insulated from the handling portion by the trench.

Abstract: A semiconductor physical quantity sensor has a P-type semiconductor substrate and an N-type semiconductor layer formed on a main surface of the P-type semiconductor substrate. A displaceable portion is formed by electrochemically etching the P-type semiconductor substrate from a side of the main surface. At that time, a buried insulation film formed to penetrate the N-type semiconductor layer and to extend into the P-type semiconductor substrate is used as a stopper for the etching. Accordingly, an etched region can be restricted by the buried insulation film, so that the displaceable portion can be precisely formed.

Abstract: A semiconductor pressure sensor includes a semiconductor substrate having a diaphragm portion. A diaphragm formation region including the diaphragm portion is electrically insulated from a peripheral region therearound. Voltage is applied to the diaphragm formation region via a pad and a wire both formed on a surface of the semiconductor substrate, for fixing a potential of the diaphragm formation region when the sensor is put in an operating state. The fixed potential is set to be equal to or higher than a maximum potential of a gauge diffusion resistive layer formed in the diaphragm formation region. As a result, even when the maximum potential of the gauge diffusion resistive layer is a power supply voltage, it can be prevented that current leaks from the gauge diffusion resistive layer.

Abstract: An acceleration sensor has a ring-shaped movable electrode connected to an anchor part via beams and a fixed electrode facing the ring-shaped movable electrode defining a specific interval, which are disposed on a substrate. The movable electrode is displaced by acceleration approximately in parallel to the substrate and contacts the fixed electrode, so that the acceleration is detected. The fixed electrode is divided into a detecting fixed electrode for contacting the movable electrode and a sensitivity controlling fixed electrode insulated from the detecting fixed electrode. Accordingly, potential differences between the movable electrode and the detecting fixed electrode and between the movable electrode and the sensitivity controlling fixed electrode are independently controlled to control sensitivity of acceleration.

Abstract: In a semiconductor pressure sensor having a diaphragm portion and strain gauges on the diaphragm portion, Al stress balance films are provided around the diaphragm portion to balance changes in stress of the strain gauges, which are produced by a change in temperature. As a result, sensor output is prevented from varying due to the change in temperature.

Abstract: A photo diode and a signal processing circuit are formed on a silicon substrate. The signal processing circuit comprises a PNP transistor and an NPN transistor. A region of the signal processing circuit on the silicon substrate is covered by an aluminum thin film functioning as a shielding film. A covered distance L(.mu.m) is defined as an overhang of the aluminum thin film from the edge of the PNP transistor, and is determined based on a ratio of a minimum current of the PNP transistor, which induces malfunction in the signal processing circuit under the solar radiation, to a current generated in the circuit element when subjected to the solar radiation without the aluminum thin film.

Abstract: A diffusion gauge is formed in a surface of a silicon substrate which has a plane orientation of (110). The diffusion gauge is disposed so that a main current thereof flows along a <110> direction perpendicular to a direction in which large stress biased in one direction generates in the surface of the silicon substrate due to distortion of a base for fixing the silicon substrate. Therefore, even when the large biased stress generates in the surface of the silicon substrate, because the <110> direction in which the main current of the diffusion gauge flows is perpendicular to the direction in which the biased stress generates, there is a little change in a resistance value of the diffusion gauge. As a result, a detection error caused by the distortion of the base can be reduced.

Abstract: When a diaphragm portion of the pressure sensor or the like is fabricated, anisotropic etching is needed. This etching is carried out by electrochemically stopped etching. During this process, a voltage is applied to the diaphragm portion. A diode is connected between said diaphragm portion and an integrated circuit to prevent the voltage from being applied to the integrated circuit connected with the diaphragm portion. The diode is obtained by shorting the base and collector of a lateral p-n-p transistor to each other. A collector region is formed offset from immediately under a conductor pattern to prevent a parasitic MOS effect from producing a channel serving as a leakage current path. Further, a heavily doped n-type diffused region acting as a channel stopper is formed along the outer periphery of the collector region.

Abstract: A photoelectric transfer device having a light receiving element and a signal processing circuit are formed in a semiconductor substrate, a silicon oxide film is formed on the light receiving element, a first aluminum thin film is deposited on the silicon substrate, and the first aluminum thin film is patterned to make a wire connected with the signal processing circuit and a protective film placed on the silicon oxide film. Thereafter, an inter-layer insulating film is deposited on the silicon substrate while covering the protective film, a portion of the inter-layer insulating film placed on the protective film is etched and removed, a second aluminum thin film is deposited on the inter-layer insulating film and the protective film, and a portion of the second aluminum thin film placed on the protective film and the protective film are successively etched and removed.

Abstract: A pair of signal voltages outputted from a bridge circuit composed of plural strain gauges are linearly amplified individually by a pair of amplifiers, whereupon a difference between the pair of signal voltages is detected. The pair of amplifiers are formed respectively in regions that are symmetrical with each other on a chip. As a result, variations in the output characteristics between the amplifiers are decreased.

Abstract: A semiconductor pressure sensor includes a diaphragm of an octagonal shape formed on a (110) silicon substrate by anisotropic etching. When a distance between two sides of the diaphragm, which are defined by intersecting lines of a (110) face and a (111) face of the silicon substrate, is represented as L1 and a length of a side of the diaphragm, which is defined by an intersecting line of the (110) face and a (100) face, is represented as L2, the diaphragm is formed so as to satisfy the following relationship:0.65<L2/L1<1.As a result, it is possible to eliminate substantially a non-linear component of the temperature characteristics of an offset voltage generated by the pressure sensor.

Abstract: A sunlight sensor is provided which detects sunlight by means of a semiconductor device and achieves the desired elevation angle characteristics. The sunlight sensor is implemented as a semiconductor device having p+ layers 10 and 11 as a light-responsive section and an n+ or n layer 9 as a light-nonresponsive section, and additionally having a light-detection element 2 which outputs a detection signal responsive to the amount of light received by the p+ layers 10 and 11. A light-transparent molding 4 is provided at least over the light-detection element 2, and additionally a light-cutoff mask 5 is provided on the transparent molding 4. The relative positions of the light-cutoff mask, the p+ layers 10 and 11, and the n+ or n layer 9 are then established.