PIEZOELECTRIC SINGLE CRYSTAL AND PRODUCTION METHOD THEREFOR

摘要

Heretofore, langasite-based single crystals grown by the Czochralski method have had a problem in that the composition of the crystals varies largely. A langasite-based single crystal is grown by the Czochralski method using a mixed gas in which oxygen is mixed with an inert gas as a growth atmosphere, and the grown crystal is annealed in nitrogen.  During the crystal growth, the temperature gradient in the furnace and convection of the melt in the crucible are controlled by adjusting the ratio of the inner diameter of the work coil to the inner diameter of the crucible, and at the same time, the pulling speed and the rotational speed of the seed crystal are adjusted so that the solid-liquid interface is flat.  Accordingly, a high-quality single crystal suitable for piezoelectric devices can be produced.