Abstract: Apparatus for zone refining rods of semiconductive material is disclosed including an RF induction work coil having a single turn lying in a plane generally transverse to the lengthwise axis of the rod and encircling the rod. The coil is part of an RF power oscillator circuit including a power amplifying device (e.g. a vacuum tube) having a control electrode and a power output electrode, the latter being connected through a voltage-blocking capacitance to an input node of an inductive-capacitive tank circuit. The tank circuit includes the work coil and a capacitance. One input side of the work coil is connected in a circuit to the input node capacitance being connected between the input node and the other input side of the work coil. A grounded center tap of the coil serves as a ground node of the tank circuit.The disclosure includes a circuit arrangement for supplying a signal of preselected magnitude to the control electrode for forcing the amplifying device toward desirable operating conditions.

Abstract: Disclosed is a method and apparatus for the automated growing of a floating zone refined, monocrystalline semiconductor rod. Two images of the molten/solid interface are separately positioned on two sensor arrays which, in addition to providing positioning feedback information, measure the diameter, the length of the molten zone and the "bag" or overhang angle of the molten semiconductor matter. The output of the sensor arrays are processed into signals which operate the zone refiner controls. There is thus provided an automated process for zone refining and monocrystalline rod growth of a semiconductor crystal from a seed crystal beginning with the tapering-out process, through the straight rod growth with a closely controlled diameter portion, to the end of the tapering-in process.