Furnace for seeded sublimation of wide band gap crystals

An induction furnace apparatus for growing semiconductor crystals by seeded sublimation growth, comprising:

• a quartz vacuum chamber;
• a cylindrical RF induction coil positioned coaxially with the quartz vacuum chamber;
• an RF power supply coupled to the RF induction coil;
• a reaction cell configured for containing a seed crystal and source material, the reaction cell defining an axial length measured as the reaction cell height along its axis of rotational symmetry;
• an arrangement of insulation layers around the cell configured for generating a thermal gradient inside the reaction cell;
• a support for placing the reaction cell inside the quartz vacuum chamber;
• wherein the RF induction coil is configured for generating a uniform electromagnetic field around the reaction cell when the reaction cell is positioned co-axially with the induction coil, coaxially to the quartz vacuum chamber, and near or at the center of the coil with respect to its axial length;
• and,
• wherein a ratio of height of the RE induction coil, measured along the axis of rotational symmetry, to the axial length of the reaction cell is from 2.5 to 4.0.