Magnetic random access memory array with free layer locking mechanism
US7211874B2 · kind B2 · utility
Assignees
Inventors
Key dates
| Filing date | Apr 6, 2004 |
| Grant date | May 1, 2007 |
| Priority date | — |
| Expiry date | Sep 19, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11C11/16
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An MTJ MRAM cell element, whose free layer has a shape induced magnetic anisotropy, is formed between orthogonal word and bit lines. The bit line is a composite line which includes a high conductivity current carrying layer and a soft adjacent magnetic layer (SAL). During operation, the soft magnetic layer concentrates the magnetic field of the current and, due to its proximity to the free layer, it magnetically couples with the free layer to produce two magnetization states of greater and lesser stability. During switching, the layer is first placed in the less stable state by a word line current, so that a small bit line current can switch its magnetization direction. After switching, the state reverts to its more stable form as a result of magnetostatic interaction with the SAL, which prevents it from being accidentally rewritten when it is not actually selected and also provides stability against thermal agitation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.