METHOD AND APPARATUS FOR GROWING INDIUM OXIDE (In203) SINGLE CRYSTALS AND INDIUM OXIDE (In203) SINGLE CRYSTAL

摘要

A method and apparatus for growing truly bulk ln₂O₃ single crystals from the melt, as well as melt-grown bulk ln₂O₃ single crystals are disclosed. The growth method comprises a controlled decomposition of initially non-conducting ln₂O₃ starting material (23) during heating-up of a noble metal crucible (4) containing the ln₂O₃ starting material (23) and thus increasing electrical conductivity of the ln₂O₃ starting material with rising temperature, which is sufficient to couple with an electromagnetic field of an induction coil (6) through the crucible wall (24) around melting point of ln₂O₃. Such coupling leads to an electromagnetic levitation of at least a portion (23.1) of the liquid ln203 starting material with a neck (26) formation acting as crystallization seed. During cooling down of the noble metal crucible (4) with the liquid ln₂O₃ starting material at least one bulk ln₂O₃ single crystal (28.1, 28.2) is formed. We named this novel crystal growth method the "Levitation-Assisted Self-Seeding Crystal Growth Method". The apparatus for growing bulk ln₂O₃ single crystals from the melt comprises an inductively heated thermal system with a noble metal crucible (4) and evacuation passages (22, 22.1) for gaseous decomposition products of ln₂O₃, while keeping very low temperature gradients. Various configurations of the induction coil (6), the noble metal crucible (4) and a lid (12) covering the crucible can be utilized to obtain very low temperature gradients, sufficient evacuation passages and a high levitation force. The electrical properties of the melt grown ln₂O₃ single crystals can be modified in a wide range by at least one heat treatment in suitable atmospheres and appropriate temperatures.