US 12,312,691 B2
Method of manufacturing polycrystalline silicon rod
Naruhiro Hoshino, Niigata (JP); Masahiko Ishida, Niigata (JP); and Tetsuro Okada, Niigata (JP)
Assigned to SHIN-ETSU CHEMICAL CO., LTD., Tokyo (JP)
Filed by Shin-Etsu Chemical Co., Ltd., Tokyo (JP)
Filed on Jun. 11, 2020, as Appl. No. 16/899,510.
Claims priority of application No. 2019-111794 (JP), filed on Jun. 17, 2019.
Prior Publication US 2020/0392627 A1, Dec. 17, 2020
Int. Cl. C23C 16/56 (2006.01); C23C 16/24 (2006.01)
CPC C23C 16/56 (2013.01) [C23C 16/24 (2013.01)] 3 Claims
OG exemplary drawing
 
1. A method of manufacturing a polycrystalline silicon rod by Siemens process, comprising:
a deposition step, wherein a frequency of current is changed from a low frequency of the current to a first high frequency of the current at a point when a diameter of polycrystalline silicon reaches a predetermined diameter while a temperature of a surface of the polycrystalline silicon rod is maintained at a predetermined first temperature; and
a cooling step after an end of the deposition step, wherein the frequency of current is gradually increased from the first high frequency of the current to a second high frequency of the current as a temperature of the polycrystalline silicon rod decreases until the temperature of the surface of the polycrystalline silicon rod reaches a predetermined second temperature from the predetermined first temperature, and wherein the current is stopped when the temperature of the surface of the polycrystalline silicon rod reaches the predetermined second temperature.