SAPPHIRE MONOCRYSTAL, METHOD OF MAKING SAID MONOCRYSTAL (VERSIONS) AND MELTING DEVICE USED THEREIN Russian patent published in 2010 - IPC C30B15/34 C30B29/20 C30B29/64 

FIELD: physics.

SUBSTANCE: disclosed are monocrystalline sapphire sheets having desirable geometrical parametres, including length which is greater than the width, which is greater than thickness. The width is not less than 28 cm and thickness variation does not exceed 0.2 cm. The monocrystals can have other geometrical parametres such as maximum thickness variation, where after growth, the crystals can essentially have a symmetrical section of the neck linked to the transition from the neck to the main body of the crystal. The method of making the sapphire monocrystal involves formation of a molten mass in a crucible having a crystalliser. The horizontal cross-section of the crucible is not circular. It has a shape coefficient of 2:1. The shape coefficient is defined as the ratio of the length of the crucible to the width of the crucible, dynamic control of the temperature gradient along the crystalliser, and drawing the monocrystal from the crystalliser.

EFFECT: invention enables making sapphire sheets with large dimensions and mass with uniform thickness at moderate production costs.

53 cl, 6 dwg