Manufacturing method of 4-inch C-directional sapphire crystal

Abstract

The invention relates to a method for growing a sapphire crystal, in particular to a method for manufacturing a 4-inch C-directional sapphire crystal by a Czochralski method. In the method, aluminum oxide is taken as a raw material and a direct pulling method is utilized; the method comprises the followings steps of assembling a heat field, heating, seeding, shouldering, growing in equal diameter, cutting off, annealing, and reducing the temperature. A crucible is an iridium crucible and the iridium crucible is provided with an iridium heat-insulation cylinder; an inner heat-insulation layer is made of highly-pure zirconium oxide and has the heat-resisting temperature of 2300 DEG C; an outer heat-insulation layer is made of highly-pure corundum and has the heat-resisting temperature of 1800 DEG C. In the cutting-off step, the crystal is cut off from a smelted solution by adopting a way of descending the crucible so as to reduce the influence on the crystal quality by heat stress. In the annealing step, the crystal is kept at the original state so that the production procedure and the energy consumption can be reduced. In the invention, according to the design of the effective heat-insulation layer, the C-directional growth of the sapphire crystal is realized; the crystal is cut off from smelted solution by adopting the way of descending the crucible so that the heat stress influence relative positions of the crystal and the heat-insulation layer can be effectively reduced; and a way of heating the iridium cylinder by induction is adopted to realize the in-situ annealing so that production procedures and cost are reduced.

Description

technical field [0001] The invention relates to a sapphire crystal growth method, in particular to manufacturing 4-inch C-direction sapphire by a pulling method. Background technique [0002] Sapphire is an α-phase single crystal of aluminum oxide, with high hardness (Mohs 9), high temperature resistance, corrosion resistance, and excellent light transmission. Sapphire crystals are widely used in semiconductor substrates, special windows and other fields. In particular, high-brightness white LEDs, as the next generation of general lighting devices, have the advantages of being green and energy-saving. Sapphire substrate is the most important substrate of gallium nitride-based white light LED, and the market demand is huge. [0003] Sapphire crystals are generally made by growing in a melt, and the most important growth methods are the Kyropoulos method, the pulling method and the crucible drop method. The direction of the sapphire crystal grown by the above method is ...

AI Technical Summary

Problems solved by technology

The direction of the sapphire crystal grown by the above method is usually in the A direction, and the substrate of the LED needs to be cut in the C direction, so there are problems such as low material utilization rate and high cost.