| 摘要 |
<p>A crucible-less zone melting device for vertical semiconductor rods, esp. silicon rods, is equipped with a h.f. induction heating coil which forms, in conjunction with at least one parallel capacitor, an oscillatory heating circuit. This circuit is linked by a coupling capacitor to the active element of the h.f. generator. The preferred active element is a series or parallel connection of MOS-power transistors. This creates a device which can be made and operated at low cost. The h.f. source supplies a sinusoidal signal and has a good efficiency, without being affected by load changes.S The fusion zone (8) in the vertical silicon rod (6) is produced by an induction heating coil (7) in an oscillatory circuit with parallel capacitors (5) which receives its energy from a h.f. generator (10) through a coaxial cable (9). The active element is represented by two pairs of MOS-transistors (11,12,13,14) which receive a feedback signal on their gates via two coils (17,18). The drains of the transistors (11,13) are connected to the mains through a choke coil (15). A coupling capacitor (16) transmits the generator signal to the heating circuit.</p> |
