Growth method for preparing square sapphire crystal by Kyropoulos process

Abstract

The invention provides a growth method for preparing a square sapphire crystal by a Kyropoulos process. The sapphire monocrystal growth technique mainly comprises the following steps: crystal seeding, shouldering, isometric growing, end pulling, and cooling and annealing. The square crucible and square heating body must be concentric during furnace loading, the side wall is parallel to the side surface of the square heating body, and the seed crystal is the square seed crystal of which both the end surface and side surface are finely oriented. In the isometric growth step, the cooling rate is increased, and the pull rate is decreased. In the end pulling step, proper heating is performed to bake the edges of the crystal end part, and the pull rate is increased, so that the crystal is automatically separated from the crucible. Cooling is performed at higher rate in the early and later periods of the cooling and annealing step; and in the intermediate period, the cooling is stopped, and the temperature is kept for some time. The growth technique is beneficial to growing the large-size high-grade square sapphire monocrystal. The technique for growing the square sapphire monocrystal has the advantage of high crystal quality, and can greatly enhance the working efficiency and the yield of the square lump material.

Description

(1) Technical field [0001] The invention relates to a growth process for sapphire single crystal growth, in particular to a growth process for preparing high-quality square sapphire crystals by a Kyropoulos method. (2) Background technology [0002] Sapphire is aluminum oxide single crystal, which has excellent optical, mechanical, chemical and electrical properties, high optical transmittance within 0.19~5.5μm, high strength, erosion resistance, corrosion resistance, high temperature resistance, and can be used in close Working under the harsh conditions of 2000°C high temperature, it is widely used in science and technology, space vehicles, windows of high-intensity lasers, national defense and civil industry, and many other fields of electronic technology. It has also become the preferred material for the current mobile phone screen market. [0003] The cold-heart shoulder micro-pulling method (SAPMAC) is a method suitable for growing high-quality sapphire single crystals...

AI Technical Summary

Problems solved by technology

[0005] The present invention uses the square sapphire single crystal furnace involved in the previous patent ZL201420050091.5 to conduct a comprehensive analysis on the problems of seeding difficulties and high crystal stress during the growth of square sapphire single crystals, and grow pear-shaped sapphire single crystals by retaining the original SAPMAC method At the same time as the advantages, the key link of the crystal growth process is designed, and a growth method for the preparation of square sapphire single crystals by the Kyropoulos method that can grow high-quality square sapphire single crystals is proposed.

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