Semiconductor memory device and method of controlling imprint condition thereof
US5953245A · kind A · utility
22Cited by
3References
20Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Oct 31, 1997 |
| Grant date | Sep 14, 1999 |
| Priority date | — |
| Expiry date | Oct 31, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11C11/22
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A semiconductor memory device with a plurality of memory cells each having a ferroelectric material for storing a data item by its residual polarization is made usable selectably both as a RAM and as a ROM by controlling the so-called "imprint condition" of the ferroelectric material. When some of the memory cells are going to be used to a ROM or when the memory cells in an imprint condition are going to be used a RAM, heat and/or voltage pulses with an appropriate polarity are applied to the data-storing ferroelectric material to change its hysteresis characteristics.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.