Method to fabricate poly tip in split-gate flash
US6165845A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 26, 1999 |
| Grant date | Dec 26, 2000 |
| Priority date | — |
| Expiry date | Apr 26, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D64/035
Abstract
A method is provided to form a sharp poly tip to improve the speed of a split-gate flash memory. The sharp poly tip is provided in place of the conventional gate bird's beak (GBB) because the latter requires the forming of thick poly-oxide which is more and more difficult in the miniaturized circuits of the ultra scale integrated technology. Furthermore, it is well known that GBB encroaches under the gate edge in a split-gate flash and degrades the programmability of submicron memory cells. The sharp poly tip of the invention is provided by forming a tapered floating gate through a high pressure etch such that the tip of the upper edge of the floating gate under the poly oxide is sharper and more robust, and, therefore, less susceptible to damage during the manufacture of the cell. The invention is also directed to a semiconductor device fabricated by the disclosed method.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.