Patent ID: 6810575
Filing Date: 2004-11-02
Classification: B82Y,C30B,H01J,H01L,Y10T

Abstract:
A method for producing a functional element for use in an electric, an electronic or an optical device, which comprises:(a) gasifying, at a temperature of from 30 to 600Â° C., at least one metal compound comprising a metal moiety and a non-metal moiety, said metal compound having volatilizability or sublimability and having the capability to react with at least one oxide-forming substance to form a metal oxide corresponding to said metal compound, to thereby obtain a metal compound gas, and (b) applying the obtained metal compound gas onto a surface of a substrate which is placed in a reaction zone containing said oxide-forming substance and which is heated to a temperature which is higher than the temperature of said metal compound gas and which is not higher than 800Â° C., to thereby contact the surface of said substrate with said metal compound gas in the presence of said oxide-forming substance for a period of time sufficient to grow a plurality of metal oxide needles on the surface of said substrate and form a functional element for use in an electric, an electronic or an optical device, said functional element comprising: a substrate having on an upper surface thereof a plurality of metal oxide single crystal needles extending upwardly of the upper surface of said substrate, with their respective central axes arranged substantially in parallel with each other, said needles having a weighted average circle-based diameter of from 0.01 to 10,000 &mgr;m, wherein said weighted average circle-based diameter is defined as the weighted average diameter of circles having areas equal to the areas of the cross-sections of said needles, said cross-sections being taken at the middle portions located at the Â½ lengths of said needles and along a plane perpendicular to the central axes of said needles, said needles having a weighted average aspect ratio of 0.1 or more, wherein said weighted average aspect ratio is defined as the ratio of the weighted average length of the needles to said weighted average circle-based diameter of the needles, said needles being present at a density of from 0.01 to 10,000 needles per unit area having a size of 10 &mgr;mÃ—10 &mgr;m at the upper surface of said substrate.