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:
May. 30, 1995
Filed:
Feb. 04, 1994
Masahiko Urano, Takasaki, JP;
Michiaki Oda, Annaka, JP;
Shin-Etsu Handotai Co. Ltd., Tokyo, JP;
Abstract
An apparatus for producing a semiconductor single-crystal grown by the Czochralski method includes a reference reflector disposed at the lower end of a gas rectifying tube, first and second optical systems disposed above the reference reflector for changing the direction of propagation of light from the horizontal to the vertical, and vice versa, a first position sensor composed of a first light source for emitting a light beam in a horizontal direction toward the first optical system, and a first photosensitive member which receives a reflection light reflected from the melt surface in a crucible, a second position sensor composed of a second light source for emitting a light beam in a horizontal direction toward the second optical system, and a second photosensitive member which receives a reflection light reflected from the reference reflector. With this construction, the distance between the gas rectifying tube and the melt surface can be detected and maintained constant throughout the crystal growth process with the result that the crystal quality, especially the concentration of dopant and impurities, such as oxygen and carbon, is uniform.