| 摘要 |
In the zone-melting of a rod of germanium of silicon using an induction heating coil, the diameter of the resolidifying interface of the molten zone is maintained at a desired constant value by stretching or compressing the ends of the rod when the voltage across the coil varies from a value corresponding to the desired diameter. The diameter of the resolidified rod may be the same as or smaller than that of the charge rod. One or both ends of the rod may be rotated. The zone melting may be effected in a vacuum or an atmosphere of argon or hydrogen. In the production of a rod without stretching (Fig. 1), the monitoring circuit comprises measuring capacitors (20 and 21), a rectifier (22), and a cathode follower (23); and the control means comprises a polarised relay (25), a direct current source (27), and a motor (29). In the production of a rod with stretching (Fig. 2), the monitoring circuit comprises measuring capacitors (90 and 91), a rectifier (92), a cathode follower (93), and an amplifier (94); and the control means comprises an alternating current source (95-96), an adjustable auto-transformer (100), a rectifier (101) and a motor (74). |
