Local shaping technique and new growth apparatus for complex sapphire products

Abstract The “local shaping technique” is one of the many versions of the Stepanov method. In contrast to the conventional Stepanov technique, in this process, the die forms only an element of the predetermined cross-section of the crystal being pulled, while the whole cross-section is obtained by means of crystal rotation. The growth of sapphire tubes by this technique is described in detail. The stability of the process is analyzed, and the structure of grown tubes is studied. A new growth technique has been developed to obtain complex sapphire products, with continous alteration of the side surface shape. The growth of cone-shaped tubes, hollow cones, and other shapes is described.