High performance MTJ element for conventional MRAM and for STT-RAM and a method for making the same
US8372661B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 31, 2007 |
| Grant date | Feb 12, 2013 |
| Priority date | — |
| Expiry date | Nov 26, 2028 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10B61/22
- WIPO fieldMicro-structural and nano-technology
- WIPO sectorChemistry
Abstract
A STT-RAM MTJ that minimizes spin-transfer magnetization switching current (Jc) is disclosed. The MTJ has a MgO tunnel barrier layer formed with a natural oxidation process to achieve a low RA (10 ohm-um2) and a Fe or Fe/CoFeB/Fe free layer which provides a lower intrinsic damping constant than a CoFeB free layer. A Fe, FeB, or Fe/CoFeB/Fe free layer when formed with a MgO tunnel barrier (radical oxidation process) and a CoFeB AP1 pinned layer in a MRAM MTJ stack annealed at 360° C. provides a high dR/R (TMR)>100% and a substantial improvement in read margin with a TMR/Rp_cov=20. High speed measurement of 100 nm×200 nm oval STT-RAM MTJs has shown a Jc0 for switching a Fe free layer is one half that for switching an amorphous CO40Fe40B20 free layer. A Fe/CoFeB/Fe free layer configuration allows the Hc value to be increased for STT-RAM applications.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.