| 摘要 |
PURPOSE:To minimize the thermal convection of covering molten material, and to decrease the thermal stress in the pulled single crystal, by placing a barrier wall in the molten material such as B2O3 covering the molten material having the same composition as the objective single crystal, and pulling the objective single crystal from the molten material. CONSTITUTION:The surface of the molten GaAs 1 in the quartz crucible 2 is covered with molten B2O3 3, the seed crystal 5 is brought into contact with the molten material 1 through the molten material 3, and the growth of a GaAs single crystal is carried out by pulling the seed crystal. In the above process, a barrier jig 6 made of e.g. pyrolytic carbon (PBN) is shifted downward by the descending device 7 according to the movement of the upper surface of the molten material 3 which descends with the progress of the pulling of the single crystal 4. The procedure is effective to prevent the movement of the heated molten material 3 in contact with the molten material 1 toward the outer circumference of the crystal 4 by thermal convection. Accordingly, the circumferential temperature of the single crystal 4 near the upper surface of the molten material 3 can be lowered, and the etch pin density in the GaAs single crystal can be suppressed to the other of 10<3>. |
