Gm Global Technolgoy Operations, Inc.

David B Hicks

Shih-Chia Chang

Adolph L Micheli

Joseph V Mantese

Jayant K Bhagat

Michael W Putty

Han-Sheng Lee

David Sturge Eddy

Chi Hung Leung

Samuel Lorincz

Qian Shi

Iulian Nedelescu

Structures and fabrication methods of micromachined all-metal relays on silicon chips are described. The relay comprises a copper blade, electroformed into the lithographically patterned areas, with suitable dimensions of 1 mm.times.2 mm.times.0.01 mm (width.times.length.times.thickness) and a plurality of longitudinal slots to facilitate fabrication of the blade. The relay is actuated by electrostatic force, and no conduction current is required to hold the relay at either 'on' or 'off' state. Preferably, the relay is used in combination with a suitable arc suppression circuit.

Integrated electrostatically-actuated micromachined all-metal

A microaccelerometer is provided for use in on-board automotive safety control and navigational systems. The microaccelerometer includes a central support body which is supported upon a backing chip, a peripheral proof mass which circumscribes the central support body, and at least one pair of microbridges, each of which are attached to both the central support body and the peripheral proof mass. The pair of microbridges extend outwardly in opposite directions from the central support body such that a longitudinal axis through each of the microbridges forms a common axis through the central support body. The microbridges are attached to the peripheral proof mass at the end opposite the central support body so as to suspend the peripheral proof mass circumferentially about the central support body and above the backing chip. Piezoelectric drivers and sensors are provided, respectively, for exciting the microbridges at their resonant frequencies, and for detecting changes in the resonant frequencies of the microbridges which occur as a function of acceleration of the peripheral proof mass. The sensors are connected to a feedback circuit which amplifies and buffers their output and provides feedback to the drivers to properly maintain the microbridges at their resonant frequencies.

Active microaccelerometer

A resonant bridge two-axis microaccelerometer is disclosed comprising polysilicon resonant bridges orthogonally attached to a silicon proof mass, such that the silicon proof mass is suspended by the resonant bridges. Acceleration in the plane of the substrate causes differential axial loads on the opposing microbridges in each pair, thereby shifting their resonant frequencies. The acceleration component aligned with a pair is measured by the difference in resonant frequencies.

Resonant-bridge two axis microaccelerometer

A method of producing a miniaturized, fixed volume, internal reference gas chamber comprising the pores of a porous material, suitable for use in a rapid response, highly precise, internal reference, solid electrolyte electrochemical-type oxygen sensor capable of detecting oxygen partial pressures in internal combustion engines operating within lean air/fuel mixtures is accomplished using a four step technique. A thin film layer of material is deposited onto a supporting substrate and patterned, said material comprises at least one component resistant to a subsequent removal step and at least one sacrificial component not resistant to the same subsequent removal step. The said material is then sealed everywhere except at an external orifice. The sacrificial component of said material is then decomposed and removed during a removal step, providing an interlocking network of porosity comprised within the porous component of said material. The internal reference gas chamber is positioned adjacent to the electrodes of the sense and pump cells comprised within the oxygen sensing device.

Automotive, internal reference, solid electrolyte, lean oxygen sensor

Method of producing a miniature internal reference gas chamber within an

A method is disclosed for forming a semiconductor tin oxide thin film on a selected region of a surface without forming the film on an adjacent region. An ink film composed of tin(II) carboxylate compound is applied to the surface and heated to partially decompose the compound. A positive photoresist layer is preferably applied to the partially decomposed layer and selectively irradiated to define a mask overlying the selected region. Unwanted photoresist material is dissolved from the adjacent region using an aqueous alkaline solution. It is found that the solution concurrently dissolves the underlying partially decomposed tin compound, without dissolving the compound protected by the mask. Thereafter, the mask is stripped, and the underlying tin compound is heated and further decomposed to produce the desired tin oxide thin film.

Method for forming patterned tin oxide thin film element

A preferred semiconductor gas sensor of this invention features a gas interaction site comprising a gas sensitive semiconductor thin film and means for heating the film to an operative temperature. The thin film and heating means are carried upon a region of a substrate that is etched opposite the site to reduce the thickness of the region and thereby reduce heat flow from the region into a surrounding region.

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Farmington Hills, MI, United States of America

David B Hicks