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:
Jul. 20, 1999
Filed:
Jun. 19, 1997
Komatsu Electronic Metals Co., Ltd., Kanagawa, JP;
Abstract
A method for fabricating a semiconductor single crystal by the MCZ method by which it is possible to pull large diameter and heavy semiconductor single crystals without breaking the contraction portion, is provided. In the contracting step, change the shape of the crystal growth interface by making the range of the temperature fluctuation caused by convection in the vicinity of the melt surface more than 5.degree. C. so as to eliminate the dislocation in the contracted portion. When a transverse magnetic field is applied by magnets 6,6, the magnetic field intensity is set below 2000 Gauss to properly change the shape of the crystal growth interface to form the contracted portion 10. Thus,even though the diameter of the contracted portion 10 is larger than normal, free dislocation is achieved. After the dislocation is eliminated, the magnetic field intensity is recovered and shoulder 11 is formed. When a cusp magnetic field is applied, the contracting is performed when the magnetic field intensity of one of the upper-and-lower magnets being increased while the magnetic field intensity of another magnet is decreased or the upper-and-lower magnets are moved in a vertical direction to make the vicinity of the melt surface similar to a longitudinal magnetic field. After dislocation is eliminated, the magnetic field intensity of the upper-and-lower magnets or the position of the magnets is recovered.