Abstract: A surface and/or bulk micromachined hermetically sealed cavity containing at least one suspended structure in a low pressure ambient, and the associated fabrication method. The cavity is bounded by a thin-film membrane and a substrate which may have a recess. The method can be used for the production, for example, of thermionic-emission vacuum tubes, gas filled tubes and electromechanical devices. In vacuum tubes the cathode is a suspended refractory filament. Other electrodes may also be suspended. In electromechanical devices the suspended members may be cantilever beams capable of low friction motion.

Abstract: A method and structure for forming a capacitive transducer having a deformable single crystal diaphragm. A first well region is formed within a semiconductor substrate in an SOI wafer having a sacrificial layer of known thickness and a top single-crystal silicon layer thereon. Next, a silicon, epitaxial layer is deposited on the top silicon layer for forming a flexible single crystal membrane. The epitaxial layer and the sacrificial layer are masked and etched to define the flexible diaphragm. An electrical insulating conformal support layer is deposited on the substrate and attached to the diaphragm so as to seal the sacrificial layer therebetween. An access opening is etched through the diaphragm, and then a wet etchant is inserted through the access opening for removing the sacrificial layer, thereby defining a diaphragm cavity between the remaining epitaxial layer and the substrate.

Abstract: A method and structure for forming a capacitive transducer having a deformable single crystal diaphragm. A first well region is formed within a semiconductor substrate in an SOI wafer having a sacrificial layer of known thickness and a top single-crystal silicon layer thereon. Next, a silicon epitaxial layer is deposited on the top silicon layer for forming a flexible single crystal membrane. The epitaxial layer and the sacrificial layer are masked and etched to define the flexible diaphragm. An electrical insulating conformal support layer is deposited on the substrate and attached to the diaphragm so as to seal the sacrificial layer therebetween. An access opening is etched through the diaphragm, and then a wet etchant is inserted through the access opening for removing the sacrificial layer, thereby defining a diaphragm cavity between the remaining epitaxial layer and the substrate.

Abstract: A surface layer and a sacrificial layer are deposited on a substrate. A conductive structural layer bridges over the sacrificial layer and is anchored to the surface layer for creating paired conductive areas. A backside opening is etched in the substrate for defining a flexible diaphragm layer of reduced thickness. The sacrificial layer is removed so that pressures exerted on the backside opening will cause a change in capacitance between the paired conductive areas. Temporary posts support the conductive structural layer as the sacrificial layer is removed.

Abstract: A polysilicon diaphragm is formed on top of a sacrificial layer deposited upon a semiconductor substrate, where the thickness of the layer is controllable. The sacrificial layer is removed to define a diaphragm cavity, which is sealed with a plug. Electrodes within the surfaces defining the cavity deflect in response to variations in pressure, while providing a very small and minimum parasitic capacitance.

Abstract: A microlamp including a polysilicon filament coated with a protective layer and enclosed by a window in a vacuum-sealed cavity.

Abstract: A dry-release method for sacrificial layer microstructure fabrication is provided in which a structural layer is anchored to a substrate and deposited on a sacrificial layer located therebetween. Thereafter, holes are etched through the structural layer. Some of the holes are covered with a polymer layer, and portions of the sacrificial layer are then etched through the uncovered holes in the structural layer, creating void areas extending to the substrate. Preferably, the void areas also include undercut areas. The void areas are then filled with a protective polymer layer, creating temporary posts that extend from the surface of the substrate to the structural layer. The sacrificial layer is then removed by means of wet etching. The temporary posts provide support for the structural layer against capillary forces which are created by the evaporation of liquids used in the wet etching process. After wet etching of the sacrificial layer is completed, the temporary posts are removed by a dry etching technique.