Title :
Perpendicular Magnetic Tunneling Junction With Double Barrier Layers for MRAM Application
Author :
Cabrera, A. Canizo ; Chang, Che-Hao ; Hsu, Chih-Cheng ; Weng, Ming-Chi ; Chen, C.C. ; Chao, C.T. ; Wu, J.C. ; Chang, Yang-Hua ; Wu, Te-Ho
Author_Institution :
Taiwan SPIN Res. Center, Yunlin Univ. of Sci. & Technol., Touliu
Abstract :
A double-barrier-layer perpendicular magnetic tunneling junction (DpMTJ) structure consisting of Si substrate/Pt/GdFeCo/AlOx/GdFeCo/FeCo/AlOx/FeCo/TbFeCo/Pt/Ti-cap was prepared by a direct current (dc) and radio frequency (RF) magnetron sputtering method. An elliptical DpMTJ element with 3.5 mumtimes2.5 mum size was fabricated using a top-down technique. A conducting atomic force microscope (CAFM) was used to obtain I-V curves of DpMTJ structures. We obtained the magnetoresistance (MR) ratio value from measured I-V curves by applying two opposite magnetic fields value of plusmn200 Oe perpendicular to the plane of film. The MR ratio was reached as high as 74% at zero applied bias voltage. Furthermore, the MR ratio decreased as bias voltage increased. It could make the DpMTJ structure to be used in the high-density MRAM devices
Keywords :
aluminium compounds; atomic force microscopy; cobalt alloys; gadolinium alloys; iron alloys; magnetic multilayers; magnetic thin films; metallic thin films; platinum; sputtered coatings; terbium alloys; titanium; tunnelling magnetoresistance; 2.5 mum; 3.5 mum; I-V curves; Pt-GdFeCo-Al2O3-FeCo-TbFeCo-Ti; Si; conducting atomic force microscope; current-voltage curves; direct current magnetron sputtering; double barrier layers; elliptical junction element; high-density MRAM devices; magnetoresistance ratio; magnetoresistive random access memory; opposite magnetic fields; perpendicular magnetic tunneling junction; plane-perpendicular magnetic fields; radio frequency magnetron sputtering; top-down technique; zero applied bias voltage; Atomic force microscopy; Atomic measurements; Magnetic field measurement; Magnetic films; Magnetic tunneling; Magnetoresistance; Radio frequency; Sputtering; Substrates; Voltage; Magnetic tunneling junction (MTJ); magnetoresistance (MR);
Journal_Title :
Magnetics, IEEE Transactions on
DOI :
10.1109/TMAG.2006.888503
