Systems for partitioned soft programming in non-volatile memory
US7535766B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Oct 13, 2006 |
| Grant date | May 19, 2009 |
| Priority date | — |
| Expiry date | Jul 26, 2027 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11C16/3418
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Soft programming is performed to narrow the threshold voltage distribution of a set of erased memory cells. Soft programming can shift the threshold voltage of memory cells closer to a verify level for the erased state. A set of memory cells can be soft programmed by soft programming portions of the set to provide more consistent soft programming rates and threshold voltages. A first soft programming pulse can be applied to a first group of cells of the set while inhibiting soft programming of a second group of cells. A second soft programming pulse can then be applied to the second group of cells while inhibiting soft programming of the first group of cells. A small positive voltage of lower magnitude than the soft programming pulses can be applied to the group of cells to be inhibited. The size of the small positive voltage can be chosen so that each memory cell of the set will experience similar capacitive coupling effects from neighboring transistors when it is undergoing soft programming.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.