LINBO3 SUBSTRATE WITH PARTIAL REVERSE POLARIZATION REGION, AND MANUFACTURE AND APPLICATION OF THE SAME

摘要

PURPOSE:To assure the application of the title LiNbO3 substrate to ultrasonic transducers, optical deflectors, optical modulators, or varieties of surface elastic wave devices all operative with high efficiency, by depositing a grating-shaped Ti film with a predetermined width on a +C surface of the LiNbO3 substrate, and heat-treating the film at a temperature slightly lower than the Curie temperature of the substrate to perform Ti thermal diffusion into the substrate, thereby making a thermal diffusion region with a reverse polarization. CONSTITUTION:Ti is vapor-deposited into a grating shape of the thickness of about 1000Angstrom on the +C surface of a LiMbO3z plate having a C axis perpendicular to a plate surface with a predetermined space, and is left in Ar gas including air or water vapor for 5-10 hours for a heat treatment. Temperature of the heat treatment is kept at about 1030 deg.C slightly lower than the Curie temperature (about 1150 deg.C) of LiNbO3. Thus, a reverse polarization region is formed into a grating shape just under the deposited Ti film, which region has a polarity opposite to its spontaneous polarization.