SINGLE CRYSTAL GROWTH FROM MELT

摘要

Crystal growth from melt is important for industry because of its high productivity. The major problems of crystal growth from melt in last 40 years were the crystal perfection and the size. The most recent problem of the melt growth is the control of crystal stoichiometry. The break-through was made by a combination of computer control and an old idea of double crucible method. The crystals used to be grown from congruent melts. By using the computerized double crucible method, crystals can be grown from the melt of any composition within the primary crystallization field, because the depleted melt due to the crystallization is recovered by the controlled supply of the charge. This technique was tried for Si crystals first without success. But it was proved to be useful in oxide crystal growth. LiNbO_3 is the first example and now the effectiveness is being realized in many other oxide crystals where controlled impurity incorporation is important.