Ultrasonic transducer fabricated as an integral part of a monolithic integrated circuit
AssigneeGeneral Electric Company
InventorWilliam R. Cady
Life of this patent
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Abstract
An array of electrostatic transducers is fabricated on a monolithic integrated circuit chip having provision for detection, amplification, and signal processing of received echoes. The transducer is multilayered with the form of a parallel plate capacitor, and is made by laterally etching an insulating layer through a small hole in the overlying layer to create a void region, then depositing a sealing layer to seal the etch holes. The upper metallic layers cover the transducer array and other monolithic circuitry and are etched to be interconnections for the various components.
Claims4
The combination on a single monolithic integrated circuit chip of an integrated ultrasonic electrostatic transducer and monolithic electronic circuitry for the amplification and signal processing of received echo signals, said electrostatic transducer comprising at least four continuous layers overlying one another on a semiconductor substrate, the first layer being made of insulating material, the second layer being insulating and having a plurality of void region apertures, the third layer projecting over said void regions with the exception of a small through-hole above every void region, the fourth layer closing said through-holes to seal off every void region and form a transducer structure capable of sensing received ultrasonic energy in which a change in the spacing between said substrate and last two layers, one of which is made of metal, results in a change of capacitance.
Dependencies are inferred from the claim text.