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:
Oct. 10, 2000
Filed:
Jul. 09, 1998
Bin-Shing Chen, Hsinchu, TW;
Winbond Electronics Corp., Hsinchu, TW;
Abstract
An improved process for fabricating flash memory cells with high control-gate-to-floating-gate coupling ratio is disclosed. The flash memory cell contains: (a) a substrate; (b) at least a pair of spaced-apart floating gates on the substrate, each of the floating gate has a pair of poly sidewall spacers; (c) a field oxide layer (FOX) partially recessed into the substrate; (d) an oxide/nitride/oxide (ONO) layer covering each of the floating gates; (e) a control gate covering the oxide/nitride/oxide layer and the field oxide layer. The design of the flash memory cell allows the field oxide layer to be wedged between the pair of floating gates and below the poly sidewall spacers. The poly sidewall spacers substantially increases the overlapping area between the control gate and the floating gate, thus allowing the control-gate-to-floating-gate coupling ratio and the performance of the flash memory to be enhanced. Also, since the field oxide layer and the floating gates are self-aligned, high density flash memory can be made from this process. Furthermore, the distance between the floating gates can be shorter than that limited by the underlying photolithography technology.