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:
Sep. 10, 1991
Filed:
Jul. 03, 1990
Nippon Mining Co., Ltd., Tokyo, JP;
Abstract
A method for producing compound semiconductor single crystal substrates which comprises the following steps, wafers of a compound semiconductor single crystal grown by the LEC method are installed in an evacuated and sealed quartz ampoule and subjected to a first annealing step at the predetermined temperature for the predetermined period, then the wafers are gradually cooled down to room temperature at the predetermined cooling speed, the cooled wafers are then subjected to etching, the etched wafers are subjected to a second annealing step at the predetermined temperature for the predetermined period in a non-oxidizing atmosphere, and finally, the wafers are gradually cooled down to room temperature.