| 摘要 |
A semiconductor capacitive transducer structure is fabricated by utilizing layers in a sacrificial wafer. By processing the sacrificial wafer, one can obtain a P+ region which is indicative of one plate of the capacitor. A carrier wafer has a dielectric layer on the top surface which includes a layer of glass. The sacrificial wafer, after being subject to diffusion of highly doped semiconductor materials, contains peripheral flange and a capacitive region which is indicative of a capacitive plate. By utilizing selective etching, one can thus form a capacitive structure on the sacrificial wafer which is bonded to the carrier wafer by means of an electrostatic bond. The flange is covered with a metallized glass sheet bonded thereto. Essentially, the thin metal layer of the glass sheet acts as a second plate for the capacitive structure. The carrier wafer may be treated so that is has an aperture which underlies the tip composite surface. This aperture defines an active deflection area to therefore enable capacitance variations with applied force. In any event, the carrier wafer can remain as a solid wafer without the aperture to therefore provide a fixed capacitor. Due to the simplicity of the techniques and the methods afforded, such devices can be easily connected in bridge arrangements or utilized in conjunction with an oscillator to provide frequency outputs which are proportional to a force applied to the active deflection area.
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