Magnetic tunnel junction (MTJ) to reduce spin transfer magnetization switching current
US7598579B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 30, 2007 |
| Grant date | Oct 6, 2009 |
| Priority date | — |
| Expiry date | May 20, 2027 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10N50/01
Abstract
A MTJ that minimizes spin-transfer magnetization switching current (Jc) in a Spin-RAM to <1×106 A/cm2 is disclosed. The MTJ has a Co60Fe20B20/MgO/Co60Fe20B20 configuration where the CoFeB AP1 pinned and free layers are amorphous and the crystalline MgO tunnel barrier is formed by a ROX or NOX process. The capping layer preferably is a Hf/Ru composite where the lower Hf layer serves as an excellent oxygen getter material to reduce the magnetic “dead layer” at the free layer/capping layer interface and thereby increase dR/R, and lower He and Jc. The annealing temperature is lowered to about 280° C. to give a smoother CoFeB/MgO interface and a smaller offset field than with a 350° C. annealing. In a second embodiment, the AP1 layer has a CoFeB/CoFe configuration wherein the lower CoFeB layer is amorphous and the upper CoFe layer is crystalline to further improve dR/R and lower RA to ≦10 ohm/μm2.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.