The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 28, 2006
Filed:
Nov. 19, 1999
Kozo Nakamura, Hiratsuka, JP;
Toshiaki Saishoji, Hiratsuka, JP;
Hirotaka Nakajima, Hiratsuka, JP;
Shinya Sadohara, Hiratsuka, JP;
Masashi Nishimura, Hiratsuka, JP;
Toshirou Kotooka, Hiratsuka, JP;
Yoshiyuki Shimanuki, Hiratsuka, JP;
Kozo Nakamura, Hiratsuka, JP;
Toshiaki Saishoji, Hiratsuka, JP;
Hirotaka Nakajima, Hiratsuka, JP;
Shinya Sadohara, Hiratsuka, JP;
Masashi Nishimura, Hiratsuka, JP;
Toshirou Kotooka, Hiratsuka, JP;
Yoshiyuki Shimanuki, Hiratsuka, JP;
Komatsu Denshi Kinzoku Kabushiki Kaisha, Hiratsuka, JP;
Abstract
A method for growing a silicon crystal by a Czochralsky method, wherein, let a pulling speed be V (mm/min) and an average value of an in-crystal temperature gradient in a pulling axis direction within a temperature range, a silicon melting point to 1350° C., be G (° C./mm), V/G ranges from 0.16 to 0.18 mm/° C. min between a crystal center position and a crystal outer periphery position, and a ratio G outer/G center of an average value G of an in-crystal temperature gradient in a pulling axis direction within a temperature range, a silicon melting point to 1350° C., at a crystal outer surface to that at a crystal center is set to up to 1.10 to thereby obtain a high-quality perfect crystal silicon wafer. Such a perfect crystal silicon wafer, wherein an oxygen concentration is controlled to up to 13×10atoms/cm, an initial heat treatment temperature is at least up to 500° C. and a temperature is raised at up to 1° C./min at least within 700 to 900° C., thereby making uniform a wafer radial distribution to an arbitrary oxygen precipitation density level.