Haynes and Boone, LLP
Magnetic tunnel junction with low defect rate after high temperature anneal for magnetic device applications
A magnetic tunnel junction is disclosed wherein the reference layer and free layer each comprise one layer having a boron content from 25 to 50 atomic %, and an adjoining second layer with a boron content from 1 to 20 atomic %. One of the first and second layers in each of the free layer and reference layer contacts the tunnel barrier. Each boron containing layer has a thickness of 1 to 10 Angstroms and may include one or more B layers and one or more Co, Fe, CoFe, or CoFeB layers. As a result, migration of non-magnetic metals along crystalline boundaries to the tunnel barrier is prevented, and the MTJ has a low defect count of around 10 ppm while maintaining an acceptable TMR ratio following annealing to temperatures of about 400° C. The boron containing layers are selected from CoB, FeB, CoFeB and alloys thereof including CoFeNiB.
TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY, LTD.
H H H H G H H H H H H
H01F H01L H01L H01F G11C H01L H01L H01L H01F H01F H01F
inventional inventional inventional inventional inventional inventional inventional inventional additional additional inventional
Huanlong Yuan-Jen Jian Po-Kang Guenole
Liu Lee Zhu Wang Jan