Refreshing ferroelectric capacitors
US5270967A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 16, 1991 |
| Grant date | Dec 14, 1993 |
| Priority date | — |
| Expiry date | Jan 16, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11C11/223
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
The endurance of ferroelectric capacitors can be extended by refreshing the ferroelectric material. The ferroelectric material is refreshed by impressing a voltage across the ferroelectric capacitor, which voltage is higher than that which the capacitor experiences during normal operation. A memory array having ferroelectric capacitive cells can be refreshed by first reading the memory cells, temporarily storing the data in associated sense amplifiers, refreshing the memory cells by impressing a higher-than-normal voltage across the ferroelectric cell capacitors, then rewriting the temporarily stored data back into the memory cells. Refresh circuits connected between the drive line and bit line common to a number of cells are driven with voltages which are higher than the memory cell experiences during normal read operations. A V.sub.cc to ground pulse train is applied to the drive line, while an inverted waveform thereof is applied to the bit line during refresh operations.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.