Measuring method null of grating constant of piezoelectric

摘要

PURPOSE: To prevent the accurate measurement of lattice constants from being hindered by coating the whole surface of a piezoelectric crystal, whose lattice constants are to be measured, with a conductive thin film. ;CONSTITUTION: A wafer 1 is made from electro-optical material used for optical devices, and the thickness thereof is d. A conductive thin film 2 is made from conductive material, whose surface, back face and whole side face are coated so as to form the thin film being t in thickness. Since lattice constants are obtained through the thin film 2 by means of X-radiation analysis, the thickness is not allowed to be so thick as to produce the crystal of the thin film. The material is to absorb little X-radiation as its characteristic. From the viewpoint of optical devices manufacturing, the material is required to disappear by oxidation, or to be removed by acid or alkali. Carbon is most suitable as the thin film, and gold, silver, or organic substance having conductivity are also available as the thin film. The thin film thickness stays normally in a range from several tens to several hundreds angstroms. The purpose of the thin film is to let charge escape, and the thin film is allowed to be studded as islets-like on the surface thereof.;COPYRIGHT: (C)1993,JPO&Japio