| 摘要 |
1415286 Zone-melting SIEMENS AG 31 Jan 1974 [18 April 1973] 04458/74 Heading B1S In the non-crucible zone melting of a crystalline semiconductor rod by an induction heating coil the formation of a desired electrical resistance profile in the zone melted rod is achieved by carrying out the zone melting in a shielding gas atmosphere wherein the flow speed, flow direction and flow temperature of the shielding gas in the region of the molten zone are so controlled as to produce changes in the material flow and temperature distribution in the molten zone and the adjacent portions of the rod. Suitable apparatus, as shown in Fig. 4, comprises a single turn flat induction heating coil 4 surrounding the molten zone 5 in a silica crystal 1, the shielding gas flowing upwards 20 is collected by a gas intake in the form of a gravity cylinder 23 and fed directly to the molten zone by means of guide vanes 22 and finally escapes upwards through the gap 28 so causing turbulence or rotation of the material in the molten zone. |
