Drift mitigation for multi-bits phase change memory
US8854872B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 22, 2011 |
| Grant date | Oct 7, 2014 |
| Priority date | — |
| Expiry date | Nov 29, 2032 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11C2013/0092
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An RC-based sensing scheme to effectively sense the cell resistance of a programmed Phase Change Material (PCM) memory cell. The sensing scheme ensures the same physical configuration of each cell (after programming): same amorphous volume, same trap density/distribution, etc. The sensing scheme is based on a metric: the RC based sense amplifier implements two trigger points. The measured time interval between these two points is used as the metric to determine whether the programmed cell state, e.g., resistance, is programmed into desired value. The RC-based sensing scheme is embedded into an iterative PCM cell programming technique to ensure a tight distribution of resistance at each level after programming; and ensure the probability of level aliasing is very small, leading to less problematic drift.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.