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Method for Fabrication of Single Crystal Perovskite Films by Melting and Graphoepitaxy

IP.com Disclosure Number: IPCOM000034743D
Original Publication Date: 1989-Apr-01
Included in the Prior Art Database: 2005-Jan-27
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Chisholm, MF: AUTHOR [+2]

Abstract

Surface topography of a substrate can have a profound effect on the orientation of a deposit. This is known for deposition from the vapor and has been suggested for solidification. The principle is that crystals which have a well-defined shape and are free to rotate can be aligned by natural or fabricated surface features on a substrate - a behavior termed graphoepitaxy. Graphoepitaxy can be used to grow superconducting perovskite materials from the melt, from vapor, or by crystallization from an amorphous deposit as characteristic tablets with the c-dimension being typically a fraction of the a and b dimensions. The designations a, b and c refer to the macroscopic edges of the tablets but also correspond to the charcteristic lengths of the crystal unit cell. Thus, aligning the tablets is equivalent to aligning the crystals.

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Method for Fabrication of Single Crystal Perovskite Films by Melting and Graphoepitaxy

Surface topography of a substrate can have a profound effect on the orientation of a deposit. This is known for deposition from the vapor and has been suggested for solidification. The principle is that crystals which have a well- defined shape and are free to rotate can be aligned by natural or fabricated surface features on a substrate - a behavior termed graphoepitaxy. Graphoepitaxy can be used to grow superconducting perovskite materials from the melt, from vapor, or by crystallization from an amorphous deposit as characteristic tablets with the c-dimension being typically a fraction of the a and b dimensions. The designations a, b and c refer to the macroscopic edges of the tablets but also correspond to the charcteristic lengths of the crystal unit cell. Thus, aligning the tablets is equivalent to aligning the crystals. Graphoepitaxy can be achieved on both crystalline and amorphous patterned substrates. It is desirable that the substrate not react with the deposit. A (100) surface of MgO is a suitable inert patternable substrate for perovskites such as 1-2-3 materials. The MgO can be patterned with the required geometry, which is a set of mutually perpendicular steps, by the following steps: (a) thermal evaporation by heating near to the melting point of MgO; (b) etching in hot (125oC) H3Po4 through a lithographically fabricated mask and, (c) preferential dissolution of...