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:
Aug. 04, 1998
Filed:
Dec. 30, 1996
Lance G Hellwig, St. Louis, MO (US);
MEMC Electronic Materials, Inc., St. Peters, MO (US);
Abstract
A method for monocrystalline epitaxial deposition which reduces the occurrence of large area defects for chemical vapor depositions carried out at near atmospheric pressure. Reactant gas is passed over a semiconductor wafer in a reaction chamber to an exhaust in a conventional manner. A venturi tube in fluid communication with the reaction chamber is adjusted to draw a vacuum pressure in the reaction chamber. The relatively small vacuum pressure produces a more laminar flow of reactant gas leaving the reaction chamber. Reduction in turbulence and eddy currents reduces the possibility that particles from matter deposited near the exhaust of the reaction chamber can be transported upstream in the gas flow onto the wafer, causing large area defects. A system for carrying out the method is also disclosed.