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. 03, 1998
Filed:
Jan. 17, 1997
Shang-De Ted Chang, Fremont, CA (US);
Binh Ly, San Jose, CA (US);
Abstract
A semiconductor fabrication process allows for the fabrication of high-voltage transistors, logic transistors, and memory cells where, as required for sub-0.3 micron device geometries, the gate oxide of the logic transistors is thinner than the tunnel oxide thickness of the non-volatile memory cells without the undesirable contamination of the gate oxide of the logic transistors or contamination of the tunnel oxide of the memory cells. In one embodiment, the tunnel oxide of the memory cells is grown to a desired thickness. In a next step, a layer of doped polysilicon which will serve as the floating gate of the memory cell(s) is immediately deposited over the tunnel oxide of the memory cells, thereby protecting the tunnel oxide from contamination in subsequent masking and etching steps. The gate oxide of the logic transistors and the gate oxide of the high-voltage transistors are then grown to a desired thickness.