# US 5,705,041 A · Method of minimizing surface effects in thin ferroelectrics > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,705,041 A - Document ID: US5705041A - Status: Granted - Kind: A - Application number: 08/225,601 - Filed: 1994-04-07 - Granted: 1998-01-06 - Earliest claimed: 1994-04-07 - Assignees: Texas Instruments Incorporated - Inventors: James F. Belcher; Howard R. Beratan - Web page: https://patentgrep.com/patent/US5705041A ## CPC - H10N 15/10: Thermoelectric devices using thermal change of the dielectric constant, e.g. working above and below the Curie point - C23C 14/021: {Cleaning or etching treatments} - H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR - C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04) ## Abstract A method of improving the responsivity of a pyroelectric device including providing a pyroelectric element of less than maximum theoretical density having holes therein extending to a surface of the element and having contaminants at the surface (22), cleaning the contaminants from the surface and metallizing the surface prior to contaminant reformation on the surface. The pyroelectric element is preferably a ferroelectric element and preferably barium strontium titanate. The step of cleaning can be by oxygen plasma, acid etch or a combination thereof. When the combination of cleaning steps is used, the step of cleaning comprises etching the surface and then oxygen cleaning the surface. ## Claims ### Claim 1 A method of improving the responsivity of a pyroelectric device comprising the steps of: (a) providing a pyroelectric element having at least one of contaminants and dislocations at a surface thereof; (b) removing said at least one of contaminants and dislocations from said surface; and (c) metallizing said surface to a thickness of from about 50 angstroms to about 2000 angstroms prior to contaminant reformation on said surface. ### Claim 2 (depends on 1) The method of claim 1 wherein said pyroelectric element is of less than maximum theoretical density and has holes therein, at least some of which extend to said surface of said element. ### Claim 3 (depends on 1) The method of claim 1 wherein said pyroelectric element is ferroelectric. ### Claim 4 (depends on 2) The method of claim 2 wherein said pyroelectric element is ferroelectric. ### Claim 5 (depends on 3) The method of claim 3 wherein said ferroelectric element is barium strontium titanate. ### Claim 6 (depends on 4) The method of claim 4 wherein said ferroelectric element is barium strontium titanate. ### Claim 7 (depends on 1) The method of claim 1 wherein said step of metallizing is completed within about one minute after said step of removing. ### Claim 8 (depends on 2) The method of claim 2 wherein said step of metallizing is completed within about one minute after said step of removing. ### Claim 9 (depends on 3) The method of claim 3 wherein said step of metallizing is completed within about one minute after said step of removing. ### Claim 10 (depends on 4) The method of claim 4 wherein said step of metallizing is completed within about one minute after said step of removing. ### Claim 11 (depends on 5) The method of claim 5 wherein said step of removing comprises an oxygen plasma cleaning. ### Claim 12 (depends on 6) The method of claim 6 wherein said step of removing comprises an oxygen plasma cleaning. ### Claim 13 (depends on 1) The method of claim 1 wherein said step of removing comprises etching said surface with hydrofluoric acid having a concentration of from about 0.01% to about 50%. ### Claim 14 (depends on 2) The method of claim 2 wherein said step of removing comprises etching said surface with hydrofluoric acid having a concentration of from about 0.01% to about 50%. ### Claim 15 (depends on 6) The method of claim 6 wherein said step of removing comprises etching said surface with hydrofluoric acid having a concentration of from about 0.01% to about 50%. ### Claim 16 (depends on 1) The method of claim 1 wherein said step of removing comprises etching said surface with hydrofluoric acid having a concentration of from about 0.01% to about 50% and then oxygen cleaning said surface. ### Claim 17 (depends on 2) The method of claim 2 wherein said step of removing comprises etching said surface with hydrofluoric acid having a concentration of from about 0.01% to about 50% and then oxygen cleaning said surface. ### Claim 18 (depends on 6) The method of claim 6 wherein said step of removing comprises etching said surface with hydrofluoric acid having a concentration of from about 0.01% to about 50% and then oxygen cleaning said surface. ### Claim 19 (depends on 1) The method of claim 1 wherein said surface includes dislocations therebelow, wherein said removing step comprises removal of contaminants from said surface and modifying the chemistry of said surface. ### Claim 20 (depends on 2) The method of claim 2 wherein said surface includes dislocations therebelow, wherein said removing step comprises removal of contaminants from said surface and modifying the chemistry of said surface. ### Claim 21 (depends on 6) The method of claim 6 wherein said surface includes dislocations therebelow, wherein said removing step comprises removal of contaminants from said surface and modifying the chemistry of said surface.