| 摘要 |
PURPOSE:To enable the production of a high-purity single crystal of Ga garnet having low contaminant content by the Czochralski process, by pulling the single crystal in an atmosphere of an inert gas having a specific oxygen partial pressure. CONSTITUTION:A polycrystalline Ga garnet 4 prepared by calcining a mixture of high-purity Ga2O3 and other rare earth element oxides such as Gd2O3, Sm2O3, etc. is put into an Ir crucible 1 which is surrounded with a ZrO2 refractory heat- insulator 2 and placed in the outer cylinder 9, and the garnet is heated and melted by electrifying the induction coil 3. A seed single crystal of Ga garnet is dipped in the molten oxide 4 and is pulled up slowly to obtain a Ga garnet single crystal 5. In the above process, the outer cylinder 9 is evacuated prior to the operation, and an inert gas such as Ne, Ar, He, etc. having an oxygen partial pressure of 20-100mm.Hg is introduced into the cylinder 9 from the inlet 10. A Ga garnet single crystal having extremely high purity can be produced stably, because the contamination of the product with Ga2O produced by the reduction of Ga2O3 can be prevented, and the gaseous IrO2 generated by the oxidation of the Ir crucible is discharged together with the inert gas from the exhaustion port 11. |
