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:
Dec. 28, 2004
Filed:
Dec. 13, 2002
Chi Nan Brian Li, Austin, TX (US);
Freescale Semiconductor, Inc., Austin, TX (US);
Abstract
A method of erasing a semiconductor nonvolatile memory (NVM) so as to compact the distribution of cell erased threshold voltages within a restricted range around a target erased threshold voltage. Erase pulses are applied to NVM cells until a determination is made by, for example, sensing total column source current that adequate erasure has been realized. An optional soft program signal may be applied subsequent to each erase pulse in order to impede over-erasure. Once erasure has been verified, the distribution of erased threshold voltages is compacted by sustaining, for a predetermined length of time, the simultaneous application of a gate voltage that is equal to the target erased threshold voltage and a highly positive drain voltage.