METHOD OF PERFORMING HEAT TREATMENT FOR FERROELECTRIC CRYSTALLINE SUBSTRATE

摘要

PURPOSE: A method of performing heat treatment for ferroelectric crystalline substrate is provided to improve the surface roughness of LiNbO3 single crystalline substrate by heating the LiNbO3 single crystalline substrate and controlling the atomic step height. CONSTITUTION: A ferroelectric crystalline substrate having a hexagonal crystalline structure is heated under the temperature of 900 or more degrees centigrade. The atomic step height of each crystalline axis is controlled according to relative positions between each ion of ferroelectric crystalline. The atomic step height of a z-axis direction corresponding to a grating constant is controlled at the z-axis direction of the crystalline axes. The atomic step height of an x-axis direction corresponding to the length on a plane is controlled at the x-axis direction of the crystalline axes. The atomic step height of a y-axis direction corresponding to the length on the plane is controlled at the y-axis direction of the crystalline axes.