PROCESS OF ZONE MELTING A SEMICONDUCTOR ROD HAVING UNDER PROCESS, A RECRYSTALLIZED PORTION AND SUPPLY PORTION TO BE RECRYSTALLIZED, EACH SEPARATED FROM THE OTHER BY A MOLTEN ZONE, INCLUDES SUPPORTING THE ROD SUBSTANTIALLY VERTICALLY BY FIRST AND SECOND HOLDERS RESPECTIVELY LOCATED AT THE FREE ENDS OF THE SUPPLY ROD PORTION AND THE RECRYSTALLIZED ROD PORTION, FORMING THE MOLTEN ZONE IN THE ROD WITH AN ANNULAR HEATING DEVICE SPACED FROM AND SURROUNDING THE ROD, RELATIVELY MOVING THE ROD AND THE HEATING DEVICE IN A SUBSTANTIALLY VERTICAL DIRECTION SO AS TO PASS THE MOLTEN ZONE ALONG THE ROD, ROTATING AT LEAST ONE OF THE END HOLDERS ABOUT THE SUBSTANTIALLY VERTICAL AXIS OF THE ROD PORTION AT THE FREE END OF WHICH THE END HOLDER IS LOCATED, RELATIVELY MOVING THE END HOLDER TOWARDS ONE ANOTHER AND LATERALLY AWAY FROM ONE ANOTHER AT PREDETERMINED SPEEDS SO AS TO INCREASE THE THICKNESS OF THE RECRYSTALLIZED ROD PORTION IN A DIRECTION RADIALLY OUTWARDLY TO THE ANNULAR HEATING DEVICE AND ROTATING THE SUPPLY ROD PORTION ABOUT AN AXIS ECCENTRIC TO THE SUBSTANTIALLY VERTICAL AXIS OF THE SUPPLY ROD PORTION. APPARATUS FOR CARRYING OUT THE FOREGOING METHOD INCLUDES SUBSTANTIALLY VERTICAL SPACED END HOLDERS SUPPORTING BETWEEN THEM A VERTICALLY EXTENDING SEMICONDUCTOR ROD HAVING A RECRYSTALLIZED PORTION AND A SUPPLY PORTION TO BE RECRYSTALLIZED DIVIDED BY A MOLTEN ZONE, MEANS FOR RELATIVELY DISPLACING THE END HOLDERS TOWARD ONE ANOTHER, AN ANNULAR HEATING DEVICE SURROUNDING AND SPACED FROM THE ROD AND ADAPTED TO FORM THE MOLTEN ZONE IN THE ROD, MEANS FOR DISPLACING THE HEATING DEVICE ALONG THE ROD SO AS TO PASS THE MOLTEN ZONE ALONG THE ROD, MEANS FOR ROTATING AT LEAST ONE OF THE END HOLDERS ABOUT ITS SUBSTANTIALLY VERTICAL AXIS, MEANS FOR DISPLACING ONE OF THE END HOLDERS IN A DIRECTION TRANSVERSE TO THE AXIS THEREOF SO THAT THE RECRYSTALLIZED ROD PORTION IS FORMED WITH A SPECIFIC DIAMETER EXTENDING IN DIRECTION TOWARD THE ANNULAR HEATING DEVICE, AND MEANS FOR ROTATING THE SUPPLY ROD PORTION ABOUT AN AXIS ECCENTRIC TO THE AXIS OF THE SUPPLY ROD PORTION.