Programming, erasing, and reading structure for an NVM cell
US7195983B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 31, 2004 |
| Grant date | Mar 27, 2007 |
| Priority date | — |
| Expiry date | Feb 17, 2025 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D62/8325
Abstract
A non-volatile memory (NVM) has a silicon germanium (SiGe) drain and a silicon carbon (SiC) source. The source being SiC provides for a stress on the channel that improves N channel mobility. The SiC also has a larger bandgap than the substrate, which is silicon. This results in it being more difficult to generate electron/hole pairs by impact ionization. Thus, it can be advantageous to use the SiC region for the drain during a read. The SiGe is used as the drain for programming and erase. The SiGe, having a smaller bandgap than the silicon substrate results in improved programming by generating electron/hole pairs by impact ionization and improved erasing by generating electron hole/pairs by band-to-band tunneling, both at lower voltage levels.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.