Motorola Corporation

Ljubisa Ristic

William C Dunn

Ronald J Gutteridge

Raymond Mervin Roop

Bertrand Francis Cambou

Daniel N Koury, Jr

Lewis E Terry

Paul T Bennett

Henry G Hughes

David F Mietus

H Ming Liaw

Frank A Shemansky, Jr

John E Schmiesing

David L Addie

Andy Mirza

Wu Koucheng

Michael F Calaway

A pressure sensor (11) and its method of fabrication include etching a V-groove (19) in a first surface (16) of a first substrate (12), bonding a second substrate (24) to the first substrate (12), thinning the second substrate (24) to form a diaphragm (32) overlying the V-groove (19), and etching a port (38) from the second surface (18) of the first substrate (12) to the V-groove (19). Tetra-methyl-ammonium-hydroxide is preferably used to anisotropically etch the V-groove (19), and an anisotropic plasma reactive ion etch is preferably used to etch the port (38).

Pressure sensor method of fabrication

A method for fabricating a monolithic semiconductor device with integrated surface micromachined structures is provided. A semiconductor substrate (10) has an interconnection layer (14) and a first sacrificial layer (16) overlying the substrate (10). Sensor areas (30) and IC areas (40) are formed by patterning the first sacrificial layer (16). A patterned sensor structural layer (32) is formed within sensor area (30) and protected by second sacrificial layer (34) and seal layer (36) while IC elements are formed in IC area (40). Subsequent to IC processing a RTA anneal is performed to relieve stress in sensor layer (32). Sensor area (30) is electrically coupled to IC area (40) and sacrificial layers (16, 34) removed to free sensor elements in sensor areas (40).

Method for fabricating a monolithic semiconductor device with integrated

An enclosure (8) for an electronic device (26) such as, for example, an accelerometer. The enclosure (8) includes a conductive semiconductor substrate (12) underlying the electronic device (26), a conductive cap (16) overlying the electronic device (26), and a power supply (25) having one or more outputs (27, 29) each with a substantially fixed potential wherein one output is electrically coupled to the conductive semiconductor substrate (12) and another output to the conductive cap (16). In a preferred embodiment, substrate ( 12 ) and cap (16) are coupled to the same power supply output (27). This coupling substantially eliminates the adverse effects of parasitic capacitances of the substrate (12) and cap (16) to reduce measurement error and EMI when a capacitive accelerometer is used as the electronic device (26).

Electronic device enclosure including a conductive cap and substrate

An environmental sensor integrated with high current drive device is provided. An environmental sensor is fabricated on a semiconductor substrate using conventional MOS process used for N-well CMOS logic and DMOS power transistors. An N-well is preferably used as a junction etch stop for micromachining of mechanical sensor components. A high voltage P-type region is used to electrically isolate the high current device from the sensor device. By locating the sensor device away from the high current drive device on a common semiconductor substrate, good performance can be achieved from the sensor even while the high current device dissipates a large amount of power.

Integrated circuit for sensing an environmental condition and producing

A three axis accelerometer includes a semiconductor substrate with a plurality of layers of conductive material formed thereon by semiconductor manufacturing techniques, with each layer defining a plane and mounted in parallel spaced relation to each other. A first of the layers is fixedly mounted and a second layer is mounted for limited movement relative to the first layer with the first and second layers forming a first capacitance varying in accordance with acceleration of the accelerometer along a first axis defined by the first and second layers. A plurality of first surfaces and a plurality of electrically isolated plates are formed as a portion of the first and the second layers, respectively, and positioned in parallel juxtaposition, with the plates being moveable relative to the first layer. The first surfaces and the plates defining mutually orthogonal second and third axes with each other and the first axis and forming capacitances which vary in accordance with acceleration in the second and third axes.

Three axes accelerometer

A collector arrangement for a magnetotransistor (10, 25, 30) and a method for making the magnetotransistor (10, 25, 30). A portion of a semiconductor substrate (11) is doped to form a base region (13). The base region is doped to form an emitter region (16, 26, 36) and a collector region (17, 27, 37) such that the collector region (17, 27, 37) surrounds and is spaced apart from the emitter region (16, 26, 36). Collector contacts (C.sub.1 -C.sub.8 and C.sub.5 '-C.sub.8 ', C.sub.13 -C.sub.16) are symmetrically formed in the collector region (17, 27, 37). In a three-dimensional magnetotransistor (10, 25) the collector contacts include split-collector contacts (C.sub.5 -C.sub.8 and C.sub.5 '-C.sub.8 ').

Method for making collector arrangement for magnetotransistor

A micromachined capacitor structure having a first anchor (12) attached to the substrate (24), a tether (13) coupled to the anchor (12) and having a portion free to move in a lateral direction over the substrate (24) in response to acceleration. A tie-bar (14) is coupled to the movable portion of the tether (13), and at least one movable capacitor plate (16) is coupled to the tie bar (13). A first fixed capacitor plate (16) is attached to the substrate (24) laterally overlapping and vertically spaced from the at least one movable capacitor plate (16).

Laterally sensitive accelerometer and method for making

Collector arrangement for magnetotransistor

A microprocessor having a monolithically integrated environmental sensor is provided. The microprocessor is shielded from an environmental signal by isolation which is specific to the type of sensor used, thereby allowing the sensor to be exposed to the environmental signal. Optionally, high current drive circuitry is integrated with the microprocessor-sensor circuit to provide a monolithic device which allows control of power loads based in part on output from an environmental sensing device.

Microprocessor having environmental sensing capability

A structure is provided to integrate bulk structure resonators into a monolithic integrated circuit chip. The chip also contains the remaining circuit components (17, 21, 24) required for the desired system function. Micromachining techniques are used to fabricate both support and a cavity (11, 27, 28) which allows mechanical vibration without interference. Alternative embodiments incorporate the use of non-piezoelectric mechanical resonators (14), quartz crystal resonators (18) and thin film piezoelectric resonators (22). Each type of resonator is used for the range of frequencies to which it is suited, providing a family of monolithic resonators capable of being used with integrated circuits having operating frequencies from a few hundred hertz to over 500 Mhz.

Monolithic circuit with integrated bulk structure resonator

A double pinned micromachined sensor (11) which utilizes a laminated film (27) having overall tensile strength formed on top of a silicon substrate (16). The laminated film (27) comprises a layer of silicon nitride (18) encapsulated by two layers of polysilicon (19, 21), the silicon nitride (18) providing overall tension for the laminated film. The laminated film (27) is supported above the silicon substrate by support posts (17) and is selectively etched to form a sensor (11, 13).

Double pinned sensor utilizing a tensile film

A micromachined capacitor structure having integral travel stops (19, 22, 22') within an active region of the capacitor is provided. The capacitor structure is formed on a substrate (11) and includes a moving capacitor plate (15) supported by one or more flexing arms (17) mechanically anchored to the substrate (11). The moving capacitor plate (15) has an active region (15) substantially parallel to the substrate (11) and separated from the substrate (11) by a first spacing. A corrugation (19) is formed in the moving capacitor plate (15) over the substrate (11) and separated from the substrate (11) by a second spacing, wherein the second spacing is smaller than the first spacing.

Micromachined capacitor structure and method for making

A magnetic field sensor is provided by a lateral bipolar transistor having a base region formed of a first conductivity type, an emitter region formed of a second conductivity type disposed in the base region for emitting charge carriers, and a collector region of the second conductivity type disposed in the base region for receiving charge carriers from the emitter region. A first and second metallic contact are connected to the collector region for splitting the collector current into first and second collector contact currents. In the presence of a magnetic field, a number of the charge carriers are deflected toward the first or the second metallic contact, depending on the orientation of the magnetic field, causing an imbalance in the first and second collector contact currents. The noise at the metallic contacts is the same as the noise of a single collector transistor which effectively correlates the noise with itself and cancels any distortion associated with the noise.

Magnetic field sensor with split collector contacts for high sensitivity

A differential capacitor structure includes a first static conductive layer and a second static conductive layer not electrically coupled to the first static conductive layer. A dynamic conductive layer is suspended between the first and second static conductive layers.

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Paradise Valley, AZ, United States of America

Ljubisa Ristic