SINGLE CRYSTAL PRODUCTION APPARATUS AND PROCESS

摘要

An apparatus and process for producing single crystals according to the Czochralski method for pulling up crystals, wherein the production efficiency and qualities of the crystals can be improved by freely controlling the temperature distribution and heat history of the crystals to be pulled up. The invention relates to a production apparatus according to the Czochralski method provided with a cylinder (19) that is airtightly joined to the ceiling of a lift chamber at the upper end thereof and is closed up to the surface of a melt in a crucible at the lower end thereof and that surrounds coaxially the pulled single crystal bar, and is characterized in that the lower end of the cylinder is provided with a heat-barrier body (25) occupying 30-95 vol.% of the space that is enclosed by the crystal surface, the inner wall of a quartz crucible and the surface of a melt and has a height corresponding to the radius of the crystal to be pulled up from the melt; a process for producing single crystals with the use of the above apparatus; a method of controlling the temperature distribution and heat history of the crystals thus pulled up; and single crystals thus produced. As the apparatus is provided with a heat-barrier body (25) having a sufficient barrier effect, it does not cause any lowering in the velocity of pulling even when the diameter of the pulled single crystal is increased, can uniform the temperature at the whole solid-liquid boundary, does not lower the convention into singl crystals, and can control readily and accurately the temperature distribution and heat history of the crystals to be pulled up.