Local Shaping and Growth from the Melt of Intricate Sapphire Articles on “Crystallization Center” Equipment

The traditional Stepanov method of growing crystals has processing limitations [1]. For example, the shape of the transverse cross section cannot be substantially changed as the crystal is pulled from the melt since the base of the melt column caught between the crystallization front and the shaper reproduces the geometry of the shaper edge. The size of the transverse cross section can be changed only within narrow limits, usually less than fractions of a millimeter, without detaching the meniscus from the shaper edge. If the meniscus detaches from the edge, the growth becomes unstable and a given crystal shape is in general not reproducible [2].