QUARTZ GLASS CRUCIBLE AND PRODUCTION OF THE CRUCIBLE

摘要

PROBLEM TO BE SOLVED: To provide a quartz glass crucible having an inner side surface area subjected to surface roughening in at least a start zone by many recesses arranged at inter-spacings of 5 mm in maximum in order to facilitate the start process based on the known quartz glass crucible having a crucible body and the inner side layer of the quartz glass. SOLUTION: A synthetic SiO2 grain layer is formed on the inside surface of a natural quartz grain layer 13. This synthetic SiO2 grain layer is heated and melted by a plasma, by which the transparent inner side layer 15 of high- purity SiO2 is formed and is simultaneously subjected to flame polishing. In succession, the surface area of the inner side layer 15 in the start zone 16 extending to encircle the circumference of the crucible body is subjected to the surface roughening by means of etching, embossing of the recessed patterns to the softened inner side surface of the crucible, inscribing of scribing lines by a polishing tool or blowing of frozen CO2 pellets, forming of a pore- containing air bubble layer by adding Si3N4 and releasing gaseous nitrogen.