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:
Mar. 30, 1999
Filed:
Feb. 13, 1998
Janet Wang, San Francisco, CA (US);
Scott D Luning, San Francisco, CA (US);
Vei-Han Chan, San Jose, CA (US);
Nicholas H Tripsas, San Jose, CA (US);
Advanced Micro Devices, Inc., Sunnyvale, CA (US);
Abstract
Aspects for forming a Flash EPROM cell with an adjustable threshold voltage are described. In a method aspect, the method includes forming a substrate structure to establish a foundation for cell formation, and forming a gate structure with a floating gate layer comprising polysilicon-germanium (poly-SiGe) of a non-uniform Ge concentration on the substrate structure. The method further includes forming source and drain regions within the substrate structure, the drain region having a different threshold voltage than the source region. In a further aspect, a Flash EPROM cell with an adjustable threshold voltage includes a substrate structure as a foundation for the cell. The cell further includes a gate structure on the substrate structure, the gate structure comprising a floating gate layer of polysilicon-germanium (poly-SiGe) of non-uniform Ge concentration. Additionally, source and drain regions are included in the substrate structure bordering the gate structure, the drain region having a differing threshold voltage than the source region.