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:
Mar. 24, 2009
Filed:
Oct. 04, 2007
Craig Printy, Buxton, ME (US);
Thanas Budri, Portland, ME (US);
Craig Printy, Buxton, ME (US);
Thanas Budri, Portland, ME (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
A system and method is disclosed for measuring a germanium concentration in a semiconductor wafer for manufacturing control of BiCMOS films. Germanium is deposited over a silicon substrate layer to form a silicon germanium film. Then a rapid thermal oxidation (RTO) procedure is performed to create a layer of thermal oxide over the silicon germanium film. The thickness of the layer of thermal oxide is measured in real time using an interferometer, an ellipsometer, or a spectroscopic ellipsometer. The measured thickness of the layer of thermal oxide is correlated to a germanium concentration of the silicon germanium film using an approximately linear correlation. The correlation enables a value of the germanium concentration in the silicon germanium film to be provided in real time.