One-time programmable unit memory cell based on vertically oriented fuse and diode and one-time programmable memory using the same
US6567301B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 9, 2001 |
| Grant date | May 20, 2003 |
| Priority date | — |
| Expiry date | Aug 9, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11C17/16
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A one-time programmable unit memory cell includes a vertically oriented fuse and an diode in series. Within the vertically oriented fuse, the current flow is substantially vertical, i.e. perpendicular to the plane of the substrate. Also, the vertically oriented fuse is placed between top and bottom conductors. This vertical placement of the elements helps to increase density of memory devices built using these unit cells. Also, vertically oriented fuses consume very little lateral area, which helps the density even further. The unit memory cell has two states, an initial state and a written (programmed) state. In the initial state, a resistance of the cell is finite because the vertically oriented fuse is left intact. In the written state, the resistance is infinite because the fuse is blown open. The cell may be programmed by applying a critical voltage across the cell enough to cause the fuse to become open. The states are detected by applying a read voltage across the memory cell. If the is not programmed, then a measurable amount flows. Otherwise, no current flows due to the open circuit. A cross-point memory array may be formed with unit memory cells formed at each cross point…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.