Scalable flash EEPROM memory cell with notched floating gate and graded source region
US7199424B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 23, 2006 |
| Grant date | Apr 3, 2007 |
| Priority date | — |
| Expiry date | Jan 23, 2026 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11C16/0458
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An memory device, and method of making same, that includes source and drain regions defining a channel region therebetween. A select gate is formed over and insulated from a first portion of the channel region. A conductive floating gate is disposed over and insulated from the source region and a second portion of the channel region. A notch is formed in the floating gate bottom surface having an edge that is either aligned with an edge of the source region or is disposed over the source region. A conductive control gate is disposed adjacent to the floating gate. By having the source region terminate under the thicker insulation region provided by the notch, the breakdown voltage of the source junction is increased. Alternately, the lower portion of the floating gate is formed entirely over the source region, for producing fringing fields to control the adjacent portion of the channel region.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.