PRODUCTION OF SINGLE CRYSTAL

摘要

PURPOSE:To grow the titled single crystal without any crystal defects by specifying the thickness of a liq. sealant and the temp. gradient in the axial direction when III-V and II-VI compd. semiconductor single crystals are grown by a liq.-capsule Czochralski method. CONSTITUTION:A seed crystal 4 is dipped in a raw material melt 2 covered with the liq. sealant 6 and pulled up while being rotated to form a single crystal 5 in a pressure vessel 7 filled with a high-pressure inert gas or gaseous N2. In this case, the thickness of the sealant 6 at the central part of the melt 2 before the growth of the single crystal 5 is adjusted to 2-8mm. The temp. gradient in the range from the surface of the sealant 6 to a position >=100mm higher than the surface is controlled to -20 deg.C/cm-0 deg.C/cm. Consequently, the escape of heat from the crystal to the sealant 6 by the horizontal heat conduction is reduced and the temp. gradient in the axial direction of the shaft 3 is also reduced in the vicinity of the center of the crystal. Accordingly, the thermal stress in the crystal is lowered and the number of defects generated in the crystal is decreased.