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Perpendicular magnetic tunneling junction (MTJ) for improved magnetoresistive random-access memory (MRAM) process

  • US 10,008,662 B2
  • Filed: 03/12/2015
  • Issued: 06/26/2018
  • Est. Priority Date: 03/12/2015
  • Status: Active Grant
First Claim
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1. A method for manufacturing a magnetoresistive random-access memory (MRAM) cell, the method including:

  • forming a bottom electrode layer over a protective layer, the bottom electrode layer having a central portion that extends through the protective layer, and a peripheral portion having a lower surface in direct contact with an upper surface of the protection layer;

    forming a magnetic tunneling junction (MTJ) over the bottom electrode layer;

    forming a top electrode layer over an upper surface of the MTJ;

    forming a dielectric hard mask over an upper surface of the top electrode layer;

    performing a first etch which thins the dielectric hard mask and extends through the top electrode layer and through regions of the MTJ unmasked by the dielectric hard mask, and through an upper surface but not a lower surface of the bottom electrode layer to define a ledge, to form a top electrode and an etched MTJ with a thinned portion of the dielectric hard mask remaining in place over the top electrode; and

    forming sidewall spacers extending from an upper surface of the thinned portion of the dielectric hard mask, along sidewalls of the top electrode and the etched MTJ, to an upper surface of the ledge of the bottom electrode layer;

    wherein the MTJ includes;

    a first ferromagnetic layer;

    an insulating barrier layer disposed over the first ferromagnetic layer; and

    a second ferromagnetic layer disposed over the insulating barrier layer, wherein magnetic polarities of the first ferromagnetic layer and the second ferromagnetic layer are perpendicular to an interface between the insulating barrier layer and the first ferromagnetic layer or the second ferromagnetic layer.

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