Title:
SILICON SINGLE CRYSTAL PRODUCED BY FLOAT ZONE METHOD AND SILICON SUBSTRATE
Document Type and Number:
Japanese Patent JP2014133702
Kind Code:
A
Abstract:
PROBLEM TO BE SOLVED: To provide a single crystal which has a diameter of 200 mm or greater throughout a length of the single crystal of at least 200 mm and consists of dislocation-free silicon.SOLUTION: A high-quality silicon single crystal is obtained as follows. The atmosphere in the container consists of an inert gas and nitrogen and has a pressure of 1.5-2.2 bar. The atmosphere is replaced continuously at a rate per hour of at least twice the volume of the container. A flat coil of an outside diameter of at least 220 mm is used for melting of a raw material rod. A single crystal is pulled down at a speed of 1.4-2.2 mm/min and rotated periodically by one set of rotation angles, and, each after rotation at a rotation angle of the set, the rotation direction is reversed. More specifically, the single crystal is rotated clockwise at a revolution speed of N1 by an angle of α1. Then, the rotation direction is reversed, and the single crystal is rotated anticlockwise at a revolution speed of N2 by an angle of α2. The rotations of α1 and α2 are repeated periodically. Appropriate selection of rotation angles leads to a high-quality silicon single crystal having stability of the shape.
Inventors:
ALTMANNSHOFER LUDWIG
GRUNDNER MANFRED
VIRBULIS JANIS
GRUNDNER MANFRED
VIRBULIS JANIS
Application Number:
JP2014088956A
Publication Date:
July 24, 2014
Filing Date:
April 23, 2014
Export Citation:
Assignee:
SILTRONIC AG
International Classes:
C30B29/06; C30B13/00; C30B13/26
Domestic Patent References:
| JPH09142988A | 1997-06-03 |
Attorney, Agent or Firm:
Fukami patent office