Lucent Technologies Inc.

Martin Haueis

Ho Bun Chan

Louis T Gomez

James F Bailey

Materials such as titanium are vapor-deposited in the presence of, e.g., oxygen to form a film on a substrate, such as to provide an adhesion layer between a silicon movable structure in an optical MEMS device and a gold layer serving as a reflecting surface. The resulting film contains titanium and oxygen. Varying the conditions under which the film is deposited varies the intrinsic stress of the film, which varies the change in substrate shape caused by the presence of the film. A film having a desired intrinsic stress may be obtained by control of the oxygen partial pressure when the film is deposited. In one embodiment, the oxygen partial pressure in the atmosphere present during titanium deposition is greater than about 2&#xd7;10Torr, and preferably between about 1&#xd7;10Torr and about 2&#xd7;10Torr.

Control of stress in metal films by controlling the atmosphere during film deposition

Materials such as titanium are vapor-deposited to form a film on a substrate while the substrate is thermally coupled to a temperature-controlling thermal source. Varying the temperature conditions of the substrate when the film is deposited varies the intrinsic stress of the film, which varies the change in substrate shape caused by the presence of the film. A film having a desired intrinsic stress may be obtained by control of the substrate temperature when the film is deposited. A stress-controlled titanium film may be used, for example, as an adhesion layer between a silicon movable structure in an optical MEMS device and a gold layer serving as a reflecting surface.

Control of stress in metal films by controlling the temperature during film deposition

A MEMS device employed in an optical switch has a position sensor configured to determine mirror orientation in the device. The position sensor includes at least one light sensor located under an etch gap defining the mirror in the switch. Change of light intensity at each light sensor due to the change in separation corresponding to the etch gap during mirror motion is measured and related to the mirror deflection angle. Information about the angle may be used to provide feedback to the motion actuator, which then may be operated to orient the mirror more accurately.

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Jena, Germany

Martin Haueis