Method for controlled soft programming of non-volatile memory cells, in particular of the flash EEPROM and EPROM type
US6381177B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 27, 2000 |
| Grant date | Apr 30, 2002 |
| Priority date | — |
| Expiry date | Oct 27, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11C16/12
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method for controlled soft programming of a plurality of non-volatile memory cells, having bulk terminals connected to one another and to a common bulk line. The method includes supplying at least one soft programming pulse to the plurality of memory cells for a time interval. In this step, a bulk voltage with a rising negative ramp is applied to the common bulk line for the time interval. By this means, the threshold voltage of the cells is increased by body effect, and initially only the most depleted cells are soft programmed, with a limited drain current. Subsequently, when the bulk voltage increases, the cells with a higher threshold voltage are also soft programmed, until all the cells have reached the required minimum threshold value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.