Local field enhancement for better programmability of antifuse PROM
US5208177A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 7, 1992 |
| Grant date | May 4, 1993 |
| Priority date | — |
| Expiry date | Feb 7, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/0002
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
The present invention provides improved programmability of antifuse elements by utilizing local enhancement of an underlying diffusion region. During an existing fabrication of a semiconductor device using antifuse elements after the access lines (usually word lines) are formed, a self-aligning trench is etched between two neighboring access lines thereby severing an underlying diffusion region. Following an etch back of the access lines' spacers a low energy, heavy dose implant dopes the exposed edges of the diffusion region resulting from the spacer etch back, as well as the bottom of the trench. An antifuse dielectric is formed followed by placing of a second conductive access line (usually the source lines) thus filling the trench to serve as the programmable antifuse element. The heavily doped areas in the diffusion region will now allow a reduction in programming voltage level, while providing a sufficient rupture of the antifuse dielectric.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.