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:
Jan. 17, 2006
Filed:
May. 30, 2003
Jochen Beintner, Wappingers Falls, NY (US);
Naim Moumen, Austin, TX (US);
Porshia S. Wrschka, Danbury, CT (US);
Jochen Beintner, Wappingers Falls, NY (US);
Naim Moumen, Austin, TX (US);
Porshia S. Wrschka, Danbury, CT (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A method of forming collar isolation for a trench storage memory cell structure is provided in which amorphous Si (a:Si) and silicon germanium (SiGe) are first formed into a trench structure. An etching process that is selective to a:Si as compared to SiGe is employed in defining the regions in which the collar isolation will be formed. The selective etching process employed in the present invention is a wet etch process that includes etching with HF, rinsing, etching with NHOH, rinsing, and drying with a monohydric alcohol such as isopropanol. The sequence of NHOH etching and rinsing may be repeated any number of times. The conditions used in the selective etching process of the present invention are capable of etching a:Si at a faster rate than SiGe.