| 摘要 |
<p>In order to produce crystals having large crystal diameters according to the floating zone process using disc-shaped induction heating coils, the applied voltage must be increased such that the required power can be induced in the melting zone. However, as the voltage increases, the probability of flashovers increases, in particular at the gap and at the power feeds of the induction heating coil. In order to reduce the risk of flashovers, insulating layers are applied to the induction coil and insulating components are inserted into the gap. The invention relates to a device for producing crystal rods according to the non-crucible floating zone (FZ) process by means of which electrical breakdowns at the HF induction heating coil are avoided. The device according to the invention consists of an induction coil (3) having a central opening (3.1) into which the main slot (3.2) serving as power feed merges. A shield (4) is arranged at a defined spacing (a) below the induction coil (3) and at least in the region (b) below the main slot (3.2) is thermally and fluidically shielded with respect to the melting zone (2.1). The shield (4) consists of a breakdown-resistant material of low dielectric loss and low thermal conductivity. In the gap (a) between the induction coil (3) and the shield (4) there is a relatively cold gas layer, which reduces in particular the gas temperature in the main slot (3.2) and the area surrounding the same.</p> |
