Radio-frequency induction heating for semiconductor crystal growth from a crucible

In the Czochralski and Kyropoulos processes, a semiconductor crystal is grown from a body of liquid contained in a cylindrical crucible. With induction heating, the crucible sits inside an electrically conducting graphite susceptor, which is surrounded by a multiple-loop copper coil carrying a high-frequency AC electric current. Heat is generated in a thin skin-depth layer at the outside surface of the susceptor by azimuthal electric currents induced in this layer by the AC magnetic field due to the coil current. A boundary-integral method was used to determine the distributions of the induced electric current and of the associated Joulean heating over the outside surfaces of the susceptor and of the graphite pedestal below the susceptor. Heat-flux distributions are presented for coils with four, eight or twelve loops and for two different vertical positions of the coil relative to the susceptor.