Abstract:
An accelerometer comprises a proof mass, a first resonant tuning fork connected to the proof mass, a second resonant tuning fork connected to the proof mass, and a flexural lever leverage system supporting the proof mass above a substrate. The flexural lever leverage system enhances an acceleration force applied to the proof mass to cause a tensile force in the first resonant tuning fork which raises its resonant frequency, and a compressive force in the second resonant tuning fork which lowers its resonant frequency. The device may be fabricated using semiconductor-based surface-micromachining technology.
Abstract:
Microfabricated filters constructed with permeable polysilicon membranes and methods for fabricating such filters. The filters include a frame structure having a plurality of openings therethrough and a permeable polysilicon membrane disposed over the openings in the frame structure. The frame structure provides support for the permeable polysilicon membrane. The pores of the filter may be smaller than the resolution limit of photolithography. The width of the pores may be as small as about 0.01 .mu.m, while the length of the pores may be as small as about 0.05 .mu.m. The filters feature a relatively high throughput due to the extremely short pore length. The filters may be fabricated utilizing standard microfabrication processes. Also, microfabricated shells constructed with permeable membranes for encapsulating microfabricated devices such as microelectromechanical structures (MEMS) and methods for fabricating such shells. The shells include a frame structure having a plurality of openings therethrough, a permeable membrane disposed on the openings through the frame structure, an optional sealing structure disposed on the permeable membrane, and a cavity bounded by the frame structure. The frame structure provides support for the permeable membrane. The permeable membrane may be a thin film layer of polysilicon having a thickness of less than about 0.3 .mu.m. The shells and methods for fabricating the shells minimize the damage incurred by the encapsulated microfabricated device during the fabrication of the shell without restricting the width of the shell. The shells may be fabricated utilizing standard microfabrication processes.
Abstract:
Mixing, modulation and demodulation using the nonlinear properties of microelectromechanical resonators and filters are described. Mixing followed by filtering is implemented using microelectromechanical filters with nonlinear input transducers. AM modulation is implemented by passing a carrier signal through the output transducer of a microelectromechanical filter. FM and FSK demodulation is accomplished using parallel banks of microelectromechanical filters. The invention can be implemented using integrated circuit technology.
Abstract:
A micromachine is lubricated in a fluid-based process. The known fluid-based process of releasing a sacrificial layer from a micromachine is followed by a fluid-based hydrophilic processing of the micromachine surfaces. A lubricating monolayer surface is then formed on the resultant hydrophilic micromachine surfaces. Afterwards, the surfaces are dried through conventional means.