Automatic program disturb with intelligent soft programming for flash cells
US6252803A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 23, 2000 |
| Grant date | Jun 26, 2001 |
| Priority date | — |
| Expiry date | Oct 23, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11C16/16
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method of erasing a flash electrically-erasable programmable read-only memory (EEPROM) device is provided which includes a plurality of memory cells. An erase pulse is applied to the plurality of memory cells. The plurality of memory cells is overerase verified and an overerase correction pulse is applied to the bitline to which the overerased memory cell is attached. This cycle is repeated until all cells verify as not being overerased. The plurality of memory cells is erase verified and another erase pulse is applied to the memory cells if there are undererased memory cells and the memory cells are again erase verified. This cycle is repeated until all cells verify as not being undererased. After erase verify is completed, the plurality of memory cells is soft program verified and a soft programming pulse is applied to the those memory cells in the plurality of memory cells which have a threshold voltage below a pre-defined minimum value. This cycle is repeated until all of those memory cells in the plurality of memory cells which have a threshold voltage below the pre-defined minimum value are brought above the pre-defined minimum value. The erase method is considered to be fi…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.