Surface modifying method for quartz glass crucible and surface modified crucible

Abstract

The present invention provides a surface modified quartz glass crucible having a transparent coating layer containing an agent for accelerating the crystallization of the crucible surface and a method for modifying a surface of the quartz glass crucible. The quartz glass crucible for pulling up a single crystal wherein the surface of the crucible has a transparent coating layer being dispersed in a siliceous matrix with an agent comprising a metal oxide or a metal carbonate for accelerating the crystallization is obtained by coating a mixed liquid containing a metal salt and a partial hydrolyzate of an alkoxy silane oligomer on the surface of the quartz glass crucible and by firing it. In this crucible, the transparent coating layer does not exfoliate because of the layer being integrally formed by firing the transparent coating layer onto the crucible, and crystal nuclei are uniformly formed on the crucible surface because of the adhered condition of the agent contained in the coating layer for accelerating the crystallization being uniformly maintained to attain a high rate of single crystallization.

Description

technical field [0001] The present invention relates to surface modification technology for quartz glass crucibles, and in particular to a method for surface modification of quartz glass crucibles used when drawing molten silicon into single crystal silicon used in semiconductors, and surface modified quartz glass crucibles. technical background [0002] As one of the causes of dislocations formed on the silicon single crystal when the silicon single crystal is drawn, cristobalite precipitated on the inner surface of the quartz glass crucible is released into the silicon melt. As a countermeasure, it is known to apply a crystallization accelerator on the inner surface of the crucible to cause early crystallization on the inner surface of the crucible (for example, Japanese Patent No. 3054362, Japanese Unexamined Patent Publication No. 8-2932, etc.). In these methods, a barium hydroxide solution is coated on the surface of a quartz glass crucible, and the barium hydroxide rea...

AI Technical Summary

Problems solved by technology

Therefore, in the manufacturing process of product inspection and handling, loading into the storage bag, etc., in the working process of installing the quartz glass crucible on the carbon base of the drawing device-used, the barium carbonate powder on the surface of the crucible easy to peel off

Peel off when handled by handling tools and operators, become spots and form uneven adhesion

Furthermore, when the storage bag is opened, the barium carbonate powder forms flying, which is harmful to the health of the operator

(2) Since the barium carbonate powder is only attached to the surface, the adhesion is very weak, the efficiency of forming a crystal nucleus is very low, and it is easy to form an excess of barium carbonate. After the barium powder is washed out and the barium carbonate powder is attached, until the crucible is used, dirt is attached to the surface, and the crucible cannot be cleaned.