Abstract:
A method of the invention includes reducing stiction of a MEMS device by providing a conductive path for electric charge collected on a bump stop formed on a substrate. The bump stop is formed by depositing and patterning a dielectric material on the substrate, and the conductive path is provided by a conductive layer deposited on the bump stop. The conductive layer can also be roughened to reduce stiction.
Abstract:
A method for reducing stiction in a MEMS device by decreasing surface area between two surfaces that can come into close contact is provided. Reduction in contact surface area is achieved by increasing surface roughness of one or both of the surfaces. The increased roughness is provided by forming a micro-masking layer on a sacrificial layer used in formation of the MEMS device, and then etching the surface of the sacrificial layer. The micro-masking layer can be formed using nanoclusters (520). When a next portion of the MEMS device is formed on the sacrificial layer (810), this portion will take on the roughness characteristics imparted on the sacrificial layer by the etch process. The rougher surface (910) decreases the surface area available for contact in the MEMS device and, in turn, decreases the area through which stiction can be imparted.
Abstract:
Methods of fabricating an electromechanical systems device that mitigate permanent adhesion, or stiction, of the moveable components of the device are provided. The methods provide an amorphous silicon sacrificial layer with improved and reproducible surface roughness. The amorphous silicon sacrificial layers further exhibit excellent adhesion to common materials used in electromechanical systems devices.
Abstract:
The invention relates to a process for forming a semiconductor component with a buried rough interface comprising: a) the formation of a rough interface (22) of predetermined roughness R2 in a first semiconductor substrate (16), with: * the selection of a semiconductor substrate (16), presenting a surface (14) with roughness R1>R2, * a thermal oxidation step for this substrate until an oxide -semiconductor interface (22) of roughness R2 is obtained, b) preparation of the oxidized surface of this first semiconductor substrate in view of assembly with a second substrate, c) the assembly of the surface of the oxide and of the second substrate.
Abstract:
An apparatus and method for a silicon-based Micro-Electro Mechanical System (MEMS) device, including a pair of silicon cover structures each having a substantially smooth and planar contact surface formed thereon; a silicon mechanism structure having a part thereof that is movably suspended relative to a relatively stationary frame portion thereof, the frame portion being formed with substantially parallel and spaced-apart smooth and planar contact surfaces; a relatively rough surface disposed between the contact surfaces of the covers and corresponding surfaces of the movable part of the mechanism structure; and wherein the contact surfaces of the cover structures form silicon fusion bond joints with the respective contact surfaces of the mechanism frame.
Abstract:
A multicolor optical image-generating device comprised of an array of grating light valves (GLVs) organized to form light-modulating pixel units for spatially modulating incident rays of light. The pixel units are comprised of three subpixel components each including a plurality of elongated, equally spaced apart reflective grating elements arranged parallel to each other with their light-reflective surfaces also parallel to each other. Each subpixel component includes means for supporting the grating elements in relation to one another, and means for moving alternate elements relative to the other elements and between a first configuration wherein the component acts to reflect incident rays of light as a plane mirror, and a second configuration wherein the component diffracts the incident rays of light as they are reflected from the grating elements. The three subpixel components of each pixel unit are designed such that when red, green and blue light sources are trained on the array, colored light diffracted by particular subpixel components operating in the second configuration will be directed through a viewing aperture, and light simply reflected from particular subpixel components operating in the first configuration will not be directed through the viewing aperture.
Abstract:
A micro-electromechanical-system (MEMS) device may be formed to include an anti-stiction polysilicon layer on one or more moveable MEMS structures of a device wafer of the MEMS device to reduce, minimize, and/or eliminate stiction between the moveable MEMS structures and other components or structures of the MEMS device. The anti-stiction polysilicon layer may be formed such that a surface roughness of the anti-stiction polysilicon layer is greater than the surface roughness of a bonding polysilicon layer on the surfaces of the device wafer that are to be bonded to a circuitry wafer of the MEMS device. The higher surface roughness of the anti-stiction polysilicon layer may reduce the surface area of the bottom of the moveable MEMS structures, which may reduce the likelihood that the one or more moveable MEMS structures will become stuck to the other components or structures.
Abstract:
Methods and systems for reducing stiction through roughening the surface and reducing the contact area in MEMS devices are disclosed. A method includes fabricating bumpstops on a surface of a MEMS device substrate to reduce stiction. Another method is directed to applying roughening etchant to a surface of a silicon substrate to enhance roughness after cavity etch and before removal of hardmask. Another embodiment described herein is directed to a method to reduce contact area between proof mass and UCAV (“upper cavity”) substrate surface with minimal impact on the cavity volume by introducing a shallow etch process step and maintaining high pressure in accelerometer cavity. Another method is described as to increasing the surface roughness of a UCAV substrate surface by depositing a rough layer (e.g. polysilicon) on the surface of the substrate and etching back the rough layer to transfer the roughness.
Abstract:
The application describes a MEMS transducer comprising a substrate having a cavity. The transducer exhibits a membrane layer supported relative to the substrate to define a flexible membrane. An upper surface of the substrate comprises an overlap region between the edge of the cavity and a perimeter of the flexible membrane where the membrane overlies the upper surface of the substrate. At least one portion of the overlap region of the upper surface of the substrate is provided with a plurality of recesses. The recesses are defined so as to extend from the edge of the cavity towards the perimeter of the flexible membrane.
Abstract:
A method of the invention includes reducing stiction of a MEMS device by providing a conductive path for electric charge collected on a bump stop formed on a substrate. The bump stop is formed by depositing and patterning a dielectric material on the substrate, and the conductive path is provided by a conductive layer deposited on the bump stop. The conductive layer can also be roughened to reduce stiction.