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:
Apr. 28, 1987
Filed:
Sep. 20, 1984
Tadashi Hirao, Itami, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
The inventive method of manufacturing a semiconductor device is carried out by slicing a silicon single crystal grown by a Czochralski method, thereby to provide a wafer (1), annealing the wafer (1) at a temperature range of 600.degree. C. to 800.degree. C. in an atmosphere including an inert gas and a small amount of oxygen for approximately 2 to 6 hours, thereby to precipitate oxygen (2) in the whole wafer (1), and then annealing the wafer (1) in the temperature range of 1000.degree. C. to 1100.degree. C. in a water vapor atmosphere including chlorine, thereby to form an oxide film (3) on the surface of the wafer (1), whereby a denuded zone (4) is formed beneath the oxide film (3) while crystal defects (5a-5d, 6) serving as a getter of impurities such as metals are formed beneath the denuded zone. In accordance with the inventive method, a denuded zone (4) having a controlled thickness can be formed in the wafer (1) without being influenced by the initial crystal defects and the oxygen concentration of the wafer.