Method of forming parylene-diaphragm piezoelectric acoustic transducers
AssigneeThe United States of America as represented by the Secretary of the Navy
InventorsCheol-Hyun Han, Eun Sok Kim
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Abstract
A micromachined acoustic transducer comprising a parylene diaphragm piezoelectric transducer. The parylene diaphragm has far lower stiffness than the silicon nitride. The method for fabricating the parylene diaphragm acoustic transducer utilizes a prestructured disphragm layer utilizing silicon nitride which is compatible with high temperature semiconductor process. A silicon nitride layer is patterned and partially removed after forming the parylene diaphragm layer in order to enhance the structural qualities of the parylene diaphragm. The diaphragm may be flat or dome-shaped.
Claims19
A method of fabricating a parylene diaphragm acoustic transducer comprising:
- depositing backside and topside silicon nitride on a deposition surface of a silicon substrate, followed by depositing layers of first Al, insulating parylene and second Al on the topside silicon nitride layer;
- depositing a second thicker parylene layer as a diaphragm;
- patterning contact holes to the bottom and top Al layers;
- releasing the diaphragm by patterning the backside silicon nitride;
- removing portions the silicon substrate by etching to release the diphragm;
- and thereafter,
- patterning the silicon nitride top side layer.
A method of fabricating a parylene diaphragm acoustic transducer comprising:
- depositing silicon nitride on a silicon substrate, followed by depositing a first conductive layer, an insulating layer, and a second conductive layer;
- depositing a zinc oxide layer adjacent the insulating layer;
- depositing a parylene layer in a form to serve as a diaphragm;
- patterning contact holes to the top and bottom conductive layers;
- releasing the diaphragm by removing the underlying silicon substrate;
- and,
- patterning the silicon nitride underlying the parylene diaphragm layer to provide further support for the parylene diaphragm layer.
A parylene diaphragm acoustic transducer comprising a silicon substrate supporting first and second conducting layers, separated by an insulating layer, and having a layer of zinc oxide ZnO in between the first and second conducting layers, and a layer of parylene serving as a diaphragm layer formed over the first and second conductive layers and formed at least in part over the zinc oxide layer.
Dependencies are inferred from the claim text.