Structure and method to fabricate high performance MTJ devices for spin-transfer torque (STT)-RAM
US8138561B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 18, 2008 |
| Grant date | Mar 20, 2012 |
| Priority date | — |
| Expiry date | Jul 18, 2030 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01F10/3272
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A STT-RAM MTJ is disclosed with a MgO tunnel barrier formed by a NOX process, a CoFeB/FeSiO/CoFeB composite free layer with a middle nanocurrent channel layer to minimize Jc0, and a Ru capping layer to enhance the spin scattering effect and increase dR/R. Good write margin is achieved by modifying the NOX process to afford a RA less than 10 ohm-μm2 and good read margin is realized with a dR/R of >100% by annealing at 330° C. or higher to form crystalline CoFeB free layers. The NCC thickness is maintained in the 6 to 10 Angstrom range to reduce Rp and avoid Fe(Si) granules from not having sufficient diameter to bridge the distance between upper and lower CoFeB layers. A FeSiO layer may be inserted below the Ru layer in the capping layer to prevent the Ru from causing a high damping constant in the upper CoFeB free layer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.