Perpendicular magnetic tunneling junction (MTJ) for improved magnetoresistive random-access memory (MRAM) process
First Claim
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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Accused Products
Abstract
A method of forming a magnetoresistive random access memory (MRAM) device including a perpendicular MTJ (magnetic tunnel junction) is provided. The method includes forming a magnetic tunneling junction (MTJ) over a bottom electrode layer. A top electrode layer is formed over an upper surface of the MTJ, and a hard mask is formed over an upper surface of the top electrode layer. A first etch is performed through the top electrode layer, through regions of the MTJ unmasked by the hard mask, to form a top electrode and an etched MTJ. Sidewall spacers are formed extending from an upper surface of the hard mask or the top electrode, along sidewalls of the top electrode and the etched MTJ, to a point below or about even with an upper surface of the bottom electrode. A resulting MRAM device structure is also provided.
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Citations
18 Claims
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1. A method for manufacturing a magnetoresistive random-access memory (MRAM) cell, the method including:
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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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for manufacturing a magnetoresistive random-access memory (MRAM) cell, the method including:
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forming a bottom electrode layer over a dielectric protective layer, the bottom electrode layer having a central portion that extends through the dielectric protective layer, and having a peripheral portion having a lower surface in direct contact with an upper surface of the dielectric protective 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 an un-doped silicate glass (USG) hard mask over an upper surface of the top electrode layer; performing a first etch which erodes the USG hard mask and which extends through the top electrode layer and through regions of the MTJ unmasked by the USG 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 an eroded portion of the USG hard mask remaining in place over an upper surface of the top electrode; forming sidewall spacers extending from an upper surface of the eroded portion of the USG hard mask, along sidewalls of the top electrode and the MTJ, to the ledge of the bottom electrode layer; and wherein the sidewalls spacers have substantially uniform width from an upper surface of the eroded portion of the USG hard mask, to the ledge of the bottom electrode layer; wherein forming the MTJ includes; forming a first ferromagnetic layer over the bottom electrode; forming an insulating barrier layer over the first ferromagnetic layer; and forming a second ferromagnetic layer 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. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A method for manufacturing a magnetoresistive random-access memory (MRAM) cell, the method including:
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forming a bottom electrode layer over a dielectric protective layer, the bottom electrode layer having a central portion that extends through the dielectric protective layer and a peripheral portion having a lower surface in direct contact with an upper surface of the dielectric protection layer; forming a magnetic tunneling junction (MTJ) over the bottom electrode layer; wherein forming the MTJ includes; forming a first ferromagnetic layer over the bottom electrode layer; forming an insulating barrier layer over the first ferromagnetic layer; and forming a second ferromagnetic layer 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; 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 through the top electrode layer and through regions of the MTJ unmasked by the dielectric hard mask, and through an upper surface of the bottom electrode layer to a depth within the bottom electrode layer to define a ledge, to form a top electrode and an etched MTJ; and forming sidewall spacers in direct contact with sidewalls of the dielectric hard mask, the top electrode and the etched MTJ;
the sidewall spacers extending from an upper surface of the dielectric hard mask, along sidewalls of the top electrode and the etched MTJ, to the ledge of the bottom electrode layer.- View Dependent Claims (18)
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Specification