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:
Apr. 09, 2002
Filed:
Jun. 19, 2001
Ceiling test mode to characterize the threshold voltage distribution of over programmed memory cells
Santosh K. Yachareni, Santa Clara, CA (US);
Kazuhiro Kurihara, Sunnyvale, CA (US);
Binh Q. Le, San Jose, CA (US);
Michael S. C. Chung, San Jose, CA (US);
Other;
Abstract
The present invention relates to flash memory systems and methods to determine the threshold voltage of core cells. In one exemplary system, there is provided a method of characterizing the high end of the threshold voltage distribution of an array of programmed cells. In accordance with the invention, an exemplary system and method are presented to apply a varying characterization signal operably through a high breakdown voltage periphery donut transistor and wordline drive transistors, which are driven into saturation by a boosted gate voltage which is higher than the applied varying characterization signal, in a manner which provides for the accurate determination of the V of the core cells, through the comparison of the conduction in a reference cell to that of the conduction in a core cell produced by a varying characterization signal applied to the core cell gate.