	US 12,227,870 B2
	Fused quartz crucible for producing silicon crystals, and method for producing a fused quartz crucible
Toni Lehmann, Oederan (DE); and Dirk Zemke, Ach (AT)
Assigned to SILTRONIC AG, Munich (DE)
Appl. No. 17/796,902
Filed by SILTRONIC AG, Munich (DE)
PCT Filed Jan. 27, 2021, PCT No. PCT/EP2021/051798 § 371(c)(1), (2) Date Aug. 2, 2022, PCT Pub. No. WO2021/156114, PCT Pub. Date Aug. 12, 2021.
Claims priority of application No. 10 2020 000 701.5 (DE), filed on Feb. 3, 2020.
Prior Publication US 2023/0109724 A1, Apr. 13, 2023
Int. Cl. C30B 15/10 (2006.01); C03B 20/00 (2006.01); C03C 17/00 (2006.01); C03C 17/02 (2006.01); C30B 29/06 (2006.01)

CPC C30B 15/10 (2013.01) [C03B 20/00 (2013.01); C03C 17/004 (2013.01); C03C 17/02 (2013.01); C30B 29/06 (2013.01); C03C 2217/91 (2013.01); C03C 2218/345 (2013.01)]

19 Claims

1. A fused quartz crucible for pulling a single crystal of silicon according to the Czochralski technique, comprising:

an inner side on which there is located an inner layer comprising fused natural quartz and synthetically obtained SiO₂, forming an inner surface, the inner layer being provided with a crystallization promoter which on heating of the fused quartz crucible during a crystal pulling, brings about crystallization of fused natural quartz and synthetically obtained SiO₂to form ß-cristobalite, wherein the concentration C of synthetically obtained SiO₂at a distance d from the inner surface of the inner layer is greater than the concentration of synthetically obtained SiO₂at a distance d2 from the surface of the inner layer, where d2 is greater than d, and the concentration C of synthetically obtained SiO₂as a function of the distance d within the inner layer is subject to the following relationships:

C[%]<=100−(d[mm]−0.25)×30 and

C[%]>=100−(d[mm]+0.25)×80.