| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing a langasite-based single crystal showing little variation of the composition in the crystal. SOLUTION: An LTGA single crystal is grown by Czochralski method using a raw material prepared by mixing a lanthanum oxide, a tantalum oxide, a gallium oxide and an aluminum oxide in an atomic ratio of La:Ta:Ga:Al=3.0:0.5:5.5-x:x, where x satisfies 0.1≤x≤0.3, under a mixture gas atmosphere of an inert gas containing oxygen in a ratio of 1.0% to 3.0% on a volume basis. During growing the crystal, the temperature gradient in a furnace and convection of the melt in a crucible are controlled by conditioning the inner diameter ratio of a work coil 5 to the crucible 3, and simultaneously, the pulling speed and the rotation speed of a seed crystal are conditioned so as to render the solid-liquid interfacial form into flat. Subsequently, while cooling the LTGA single crystal after grown, the crystal is annealed at a temperature of 700-900°C for 5-24 hours under an inert gas atmosphere or a mixture gas atmosphere of an inert gas and oxygen gas. COPYRIGHT: (C)2010,JPO&INPIT |
