High speed flash memory cell structure and method
US5760438A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 4, 1997 |
| Grant date | Jun 2, 1998 |
| Priority date | — |
| Expiry date | Feb 4, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D30/683
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A fast, fieldless flash memory cell includes an erase node having a control gate and a floating gate, both formed of polycrystalline silicon, a program transistor sharing the floating gate and control gate with the erase node, and a read transistor sharing the floating gate and control gate with the erase node and program transistor. The inventive memory cell is suitable for use in fast Programmable Logic Devices (PLDs) in the sub 5 nS range (2-5 nS), and other logic and memory parts. The erase node includes a buried N+ drain region in a P-type substrate, a buried implant plate doped N-type adjacent the drain region in the substrate, a tunnel oxide disposed over at least a portion of the plate and the drain region, the tunnel oxide extending into and abutting a gate oxide region, and thence to a field oxide region in a relaxed fashion, a polycrystalline silicon floating gate disposed over the field oxide, gate oxide, and tunnel oxide regions, a sandwich of ONO on the floating gate, and a polycrystalline silicon control gate (poly 2) disposed on the ONO. Programming occurs through the programming transistor. Reading occurs through a read path including the read transistor. During pr…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.