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:
Oct. 30, 2001
Filed:
Sep. 17, 1998
Applicant:
Inventors:
Helmut Strack, München, DE;
Jens-Peer Stengl, Grafrath, DE;
Assignee:
Infineon Technologies AG, Munich, DE;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01L 2/1311 ;
U.S. Cl.
CPC ...
H01L 2/1311 ;
Abstract
Residual oxygen impurities are eliminated from silicon wafers pulled from a crucible (Czochralski silicon). A multitude of trenches are etched into the back side of the crucible-pulled silicon wafer and the wafer is subsequently heat-treated at about 1100° C. The very large surface area at the front side of the silicon wafer allows oxygen impurities to diffuse out effectively. After the diffusion has been carried out, the trenches are filled with heavily doped polysilicon without leaving gaps.