MANUFACTURE OF SINGLE CRYSTAL

PURPOSE:To obtain efficiently and at low cost a single crystal material having a uniform and desired composition by preparing a single crystal while keeping the depth of the melt of a solid crystal material in a crucible at a fixed value. CONSTITUTION:A heating furnace 1 has a temp. distribution wherein the central part in the vertical and the horizontal direction is at the highest temp. and the temp. decreases as the distance from the central part increases. A solid crystal material 10 which is powdery, granular, or pelletal is supplied from a raw material supply mechanism 8 into a crucible 4 on a support 5 which is moved by a crucible moving mechanism 6. The material in the crucible 2 is heated by the furnace 1 and melted to obtain a melt 4, from which a single crystal 3 is grown by moving the crucible 2 downward at a specified velocity by the mechanism 6. Meanwhile, the weight and the volume of the crystal 3 and the melt 4 are continuously or intermittently detected by a weighing device 12 and a device 13 for detecting the upper surface position of the melt and through a programmable controller 14, and the supply of the material 10 is controlled so as to obtain a fixed depth of the melt 4. The long and large single crystal 3 having uniform composition can be obtained in this way.