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:
Feb. 04, 1997
Filed:
Nov. 22, 1994
Fernand Dorleans, Wappingers Falls, NY (US);
Liang-Choo Hsia, Stormville, NY (US);
Louis L Hsu, Fishkill, NY (US);
Gerald R Larsen, Cornwall, NY (US);
Geraldine C Schwartz, Poughkeepsie, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
The present invention is directed to a unique method for fabricating a silicon based MOS transistor having an inverse-T refractory metal gate structure. The gate fabricated according to this invention comprises a main CVD tungsten portion and a lower sputtered tungsten portion outwardly extending from the bottom of the CVD portion such that a cross section of the gate appears as an inverted 'T'. A Cl.sub.2 /O.sub.2 plasma etch is used to etch the CVD tungsten layer and a chemical etch is used to etch the sputtered tungsten layer to form the gate electrode. It has been discovered that sputtered tungsten is more resistant to Cl.sub.2 /O.sub.2 reactive ion etch than is CVD tungsten. The sputtered tungsten layer acts as a shield to protect the underlying gate oxide layer from ion damage throughout the fabrication process.