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:
Nov. 04, 2008
Filed:
Jul. 14, 2005
Ichiro Yamamoto, Kawasaki, JP;
Ichiro Yamamoto, Kawasaki, JP;
NEC Electronics Corporation, Tokyo, JP;
Abstract
A semiconductor device is provided which is capable of improving its reliability by using a material having a high relative dielectric constant as a material for its gate insulating film, by suppressing degradation of an EOT (Equivalent Oxide Thickness) and by preventing crystallization of the material having a high relative dielectric constant. The semiconductor device (Field Effect Transistor) has a silicon substrate, a seed layer made up of silicon oxide, a gate insulating film made of amorphous hafnium aliminate and a gate electrode made up of polycrystalline silicon formed the gate insulating film. The gate insulating film is so formed that a hafnium concentration decreases monotonously or step by step, whereas an aluminum concentration increases monotonously or step by step along a direction of a thickness of the gate insulating film from the silicon substrate side toward the gate electrode. In a boundary region between a lower layer side region and an upper layer side region in the gate insulating film, the hafnium and aluminum concentrations change continuously.