A method and apparatus for positively introducing dopants into semiconductor crystals via crucible-free zone melting whereby a polycrystalline rod is mounted at opposite ends thereof in a housing which includes an annular induction heating coil surrounding a section of the rod for producing a melt zone at such section and a thin dopant source rod having a predetermined amount of dopant therein is controllably fed into the melt zone so that a positively determinable amount of dopant is provided in the recrystallized rod.
