Low resistance tunneling magnetoresistive sensor with natural oxidized double MgO barrier
US8557407B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 6, 2010 |
| Grant date | Oct 15, 2013 |
| Priority date | — |
| Expiry date | Nov 28, 2031 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/1143
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A high performance TMR sensor is fabricated by incorporating a tunnel barrier having a Mg/MgO/Mg configuration. The 4 to 14 Angstroms thick lower Mg layer and 2 to 8 Angstroms thick upper Mg layer are deposited by a DC sputtering method while the MgO layer is formed by a NOX process involving oxygen pressure from 0.1 mTorr to 1 Torr for 15 to 300 seconds. NOX time and pressure may be varied to achieve a MR ratio of at least 34% and a RA value of 2.1 ohm-um2. The NOX process provides a more uniform MgO layer than sputtering methods. The second Mg layer is employed to prevent oxidation of an adjacent ferromagnetic layer. In a bottom spin valve configuration, a Ta/Ru seed layer, IrMn AFM layer, CoFe/Ru/CoFeB pinned layer, Mg/MgO/Mg barrier, CoFe/NiFe free layer, and a cap layer are sequentially formed on a bottom shield in a read head.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.