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Title: Perpendicular magnetic tunnel junction with thin CoFeB/Ta/Co/Pd/Co reference layer

Integration of high density spin transfer torque magnetoresistance random access memory requires a thin stack (less than 15 nm) of perpendicular magnetic tunnel junction (p-MTJ). We propose an innovative approach to solve this challenging problem by reducing the thickness and/or moment of the reference layer. A thin reference layer structure of CoFeB/Ta/Co/Pd/Co has 60% magnetic moment of the conventional thick structure including [Co/Pd] multilayers. We demonstrate that the perpendicular magnetization of the CoFeB/Ta/Co/Pd/Co structure can be realized by anti-ferromagnetically coupling to a pinned layer with strong perpendicular anisotropy via Ruderman-Kittel-Kasuya-Yosida exchange interaction. The pMTJ with thin CoFeB/Ta/Co/Pd/Co reference layer has a comparable TMR ratio (near 80%) as that with thick reference layer after annealing at 280 °C. The pMTJ with thin reference layer has a total thickness less than 15 nm, thereby significantly increasing the etching margin required for integration of high density pMTJ array on wafers with form factor of 300 mm and beyond.
Authors:
; ; ; ; ; ; ; ; ; ;  [1]
  1. Avalanche Technology, 46600 Landing Parkway, Fremont, California 94538 (United States)
Publication Date:
OSTI Identifier:
22391953
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 19; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ANISOTROPY; ANNEALING; COBALT; COBALT COMPOUNDS; ETCHING; EXCHANGE INTERACTIONS; IRON BORIDES; LAYERS; MAGNETIC MOMENTS; MAGNETIZATION; MAGNETORESISTANCE; PALLADIUM; RANDOMNESS; SUPERCONDUCTING JUNCTIONS; TANTALUM; THICKNESS; TUNNEL EFFECT