| 摘要 |
PURPOSE:To reduce the deformation of a crucible and to make the melting of the residual melt easy by bringing the crucible downward upon ending of the growth of a single crystal by a pulling method, starting solidification from the lower part of the residual raw material and applying mechanical oscillation to the crucible. CONSTITUTION:A melt 7 remains in a crucible 6 after the growth of a single crystal 4. Thereupon, the high frequency output of a work coil 2 is decreased at a specified rate to start decreasing the temp. in the furnace; at the same time, a crucible 6 covered with refractory materials 5, 8 installed in the upper part of an alumina pedestal 9 is moved downward at a specified rate by a vertical driving device 10. Mechanical oscillations are applied intermittently to the crucible 6 in this stage in parallel with the descending. Then, the solidification progresses from the lower to upper part of the crucible 6. The solidification is completed when a slight gap part is formed circumferentially between the crucible wall and the solidified residual melt on the side wall of the crucible 6; further, many cracks are formed in the melt by the oscillation. The residual melt solidified by the fresh additional charge is thus melted in a short time. |
