	US 12,480,225 B2
	Method for producing silicon semiconductor wafers having low concentrations of pinholes
Sergiy Balanetskyy, Freiberg (DE); and Matthias Daniel, Freiberg (DE)
Assigned to Siltronic AG, Munich (DE)
Appl. No. 17/619,064
Filed by SILTRONIC AG, Munich (DE)
PCT Filed Jun. 2, 2020, PCT No. PCT/EP2020/065179 § 371(c)(1), (2) Date Dec. 14, 2021, PCT Pub. No. WO2020/249422, PCT Pub. Date Dec. 17, 2020.
Claims priority of application No. 102019208670.5 (DE), filed on Jun. 14, 2019.
Prior Publication US 2022/0356601 A1, Nov. 10, 2022
Int. Cl. C30B 15/20 (2006.01); C30B 29/06 (2006.01)

CPC C30B 29/06 (2013.01) [C30B 15/20 (2013.01)]

12 Claims

1. A method for producing silicon wafers, comprising:

melting polysilicon in a crucible,

pulling a single crystal having a diameter greater than 200 mm in a Czochralski pulling system, dividing the single crystal into crystal pieces and

cutting the crystal pieces into wafers, further comprising:

purging the pulling system with a purge gas during the melting of the polysilicon, wherein the following relationship applies to the flow rate f of the purge gas and the pressure p in the pulling system during the melting of the polysilicon:

flow rate f[l/h]>400×pressure p[mbar],

wherein the pressure p in the pulling system is less than 7 mbar.