# US 2006/0079006 A1 · Method for forming polarization reversal > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2006/0079006 A1 - Document ID: US20060079006A1 - Status: Published application - Kind: A1 - Application number: 11/083,735 - Filed: 2005-03-18 - Published: 2006-04-13 - Earliest claimed: 2004-03-18 - Assignees: Sumitomo Osaka Cement Co., Ltd.; National Institute for Materials Science - Inventors: Futoshi Yamamoto; Junichiro Ichikawa; Satoshi Oikawa; Sunao Kurimura; Kenji Kitamura - Web page: https://patentgrep.com/patent/US20060079006A1 ## CPC - G02F 1/3558: {Poled materials, e.g. with periodic poling; Fabrication of domain inverted structures, e.g. for quasi-phase-matching [QPM]} - Y10T 29/4902: Electromagnet, transformer or inductor - G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract The present invention provides a method for forming a ferroelectric spontaneous polarization reversal capable of forming a ferroelectric spontaneous polarization reversal condition homogeneously within the ferroelectric spontaneous polarization reversal region even across a large region of 50 μm and over in width of a ferroelectric spontaneous polarization reversal. Also, it provides a method for forming a ferroelectric spontaneous polarization reversal where a ferroelectric substrate has convexo-concave structure, such as ridge structure and the like, on its surface and the polarity of the region including one portion of said convex part is reversed with accuracy. A method for forming a ferroelectric spontaneous polarization reversal in a desired region of a ferroelectric substrate 1 has a feature that said desired region 20 of a surface of said ferroelectric substrate is sprayed with micro-hard materials, made an impact by using a striking member that has micro tip diameter, or rubbed with micro-hard materials that are dispersively located on the surface of the substrate to thereby generate nucleuses, and subsequently, a given voltage is applied into said desired region to thereby form a ferroelectric spontaneous polarization reversal in said desired region of said ferroelectric substrate. Also, a method for forming a ferroelectric spontaneous polarization reversal where a convexo-concave structure is formed on a top face of a ferroelectric substrate firstly, and then, a ferroelectric spontaneous polarization region is formed on the substrate including one portion of said convex part, has a feature that a concave portion is formed on a bottom face of the substrate within the region where a ferroelectric spontaneous polarization reversal is to be formed and at least said convex portion is formed, and then, an electric field is applied into said substrate. ## Claims ### Claim 1 A method for forming a ferroelectric spontaneous polarization reversal in a desired region of a ferroelectric substrate, comprising the steps of spraying the desired region of a surface of said ferroelectric substrate with micro-hard materials, impacting the surface using a striking member that has a micro tip diameter, or rubbing with micro-hard materials that are dispersively located on the surface of the substrate, and, then applying a given voltage into said desired region to thereby form a ferroelectric spontaneous polarization reversal in said desired region of said ferroelectric substrate. ### Claim 2 A method for forming a ferroelectric spontaneous polarization reversal in a desired region of a ferroelectric substrate, comprising the steps of forming, for said desired region of a surface of the ferroelectric substrate, an electrode pattern or a mask pattern composed of aggregates of micropatterns, then applying a given voltage is applied into said desired region. ### Claim 3 A method for forming a ferroelectric spontaneous polarization reversal in a desired region of a ferroclectric substrate, wherein thickness of substrate in said desired region of said ferroclectric substrate is thinner than a region outside said desired region of the substrate, comprising the step of applying a given voltage is into said desired region to thereby form a ferroelectric spontaneous polarization reversal in said desired region of said ferroelectric substrate. ### Claim 4 (depends on 3) The method for forming a ferroelectric spontaneous polarization reversal according to claim 3, wherein a surface of the ferroelectric substrate is etched in order to make said ferroelectric substrate thinner. ### Claim 5 (depends on 3) The method for forming a ferroelectric spontaneous polarization reversal according to claim 3, wherein a face for forming said ferroclectric substrate thinly is different from a face for forming a waveguide on said ferroelectric substrate. ### Claim 6 A method for forming a ferroelectric spontaneous polarization reversal, comprising the steps of forming a convexo-concave structure on a top face of a ferroelectric substrate firstly, and then forming a ferroelectric spontaneous polarization region on the substrate including one portion of said convex part, wherein a concave portion is formed on a bottom face of the substrate within a region where a ferroelectric spontaneous polarization reversal is to be formed and at least said convex portion is formed, and then, applying an electric field into said substrate. ### Claim 7 (depends on 6) The method for forming a ferroclectric spontaneous polarization reversal according to claim 6, wherein depth of said concave portion on the bottom face of the substrate is greater than height of the convex portion on the top face of the substrate. ### Claim 8 (depends on 6) The method for forming a ferroelectric spontaneous polarization reversal according to claim 6, wherein width of said concave portion on the bottom face of the substrate is wider than width of said convex portion on the top face of the substrate. ### Claim 9 (depends on 6) The method for forming a ferroelectric spontaneous polarization reversal according claim 6, wherein said electric field is applied via liquid electrode. ### Claim 10 (depends on 6) The method for forming a ferroelectric spontaneous polarization reversal according to claim 6, wherein at least one portion of a region outside said concave portion on the bottom face of the substrate is removed after forming a ferroelectric spontaneous polarization reversal. ### Claim 11 (depends on 6) The method for forming a ferroelectric spontaneous polarization reversal according to claim 6, wherein said concave portion on the bottom face of the substrate is filled entirely or partially with a material that has almost equal dielectric constant or coefficient of thermal expansion of said substrate after forming a ferroelectric spontaneous polarization reversal. ### Claim 12 A method for forming a ferroelectric spontaneous polarization reversal, comprising the steps of forming a concave portion on a top face of a ferroelectric substrate or a bottom face of a ferroelectric substrate, and applying an electric field into the substrate, wherein a ferroelectric spontaneous polarization reversal is formed at least in one portion of a region of said substrate with said concave portion, and wherein shape of said concave portion is configured such that width of said concave portion gets narrower gradually toward an inside of the substrate. ### Claim 13 (depends on 12) The method for forming a ferroelectric spontaneous polarization reversal according to claim 12, further comprising the steps of: after the first forming of the ferroelectric spontaneous polarization reversal, the top face of the substrate or the bottom face of the substrate that has already formed said concave portion is made almost a flat-plane, and then, a new concave portion is formed in a region where no concave portion was formed previously, and then an electric field is applied into said substrate to form a ferroelectric spontaneous polarization reversal again at least in one portion of the region of the substrate with said new concave portion. ### Claim 14 (depends on 12) The method for forming a ferroelectric spontaneous polarization reversal according to claim 12, wherein the concave portions formed on the top and bottom faces of said substrate are placed in different geometric locations where following ferroelectric spontaneous polarization reversal regions corresponding to said concave portions do not overlap respectively. ### Claim 15 (depends on 12) The method for forming a ferroelectric spontaneous polarization reversal according to claim 12, wherein said applied electric field is gradually increased from a weak electric field including 0 to a given value of the electric field. ### Claim 16 (depends on 12) The method for forming a ferroelectric spontaneous polarization reversal according to claim 12, wherein said electric field is applied via liquid electrode. ### Claim 17 (depends on 7) The method for forming a ferroelectric spontaneous polarization reversal according to claim 7, wherein width of said concave portion on the bottom face of the substrate is wider than width of said convex portion on the top face of the substrate. ### Claim 18 (depends on 6) The method for forming a ferroelectric spontaneous polarization reversal according claim 6, wherein said electric field is applied via liquid electrode. ### Claim 19 (depends on 12) The method for forming a ferroelectric spontaneous polarization reversal according to claim 12, wherein said applied electric field is gradually increased from a weak electric field including 0 to a given value of the electric field. ### Claim 20 (depends on 12) The method for forming a ferroelectric spontaneous polarization reversal according to claim 12, wherein said electric field is applied via liquid electrode.