Patent ID: 11917835
Assignee: INTERNATIONAL BUSINESS MACHINES CORPORATION
Field: nan (nan)
Classification: CPC H | IPC H

Claim 0:
1. A semiconductor structure of a funnel-shaped spin transfer torque (STT) magnetoresistive random-access memory (MRAM) device with a dual magnetic tunnel junction, the semiconductor structure comprising:
a metal pillar on a connection to a semiconductor device;
a first reference layer on the metal pillar and on a portion of a first interlayer dielectric adjacent to the metal pillar;
a first tunnel barrier on the first reference layer;
a free layer on the first tunnel barrier layer, wherein the free layer is a synthetic antiferromagnet (SAF) comprising a first free layer, a non-magnetic spacer, and a second free layer, and wherein the first free layer and the second free layer are comprised of magnetic bilayers to make a SAF with strong anti-ferromagnetic coupling;
a second tunnel barrier on the free layer; and
a second reference layer on the second tunnel barrier,
wherein a first portion, or vertical portion, of the first reference layer, the free layer, and the second reference layer on a side wall of the metal pillar is thicker than a second portion, or horizontal portion, of the first reference layer, the free layer, and the second reference layer on a horizontal surface above a semiconductor wafer surface and on a horizontal surface above a flat top of the metal pillar, wherein a thickness of the free layer on the side wall of the metal pillar ranges from 15 to 25 angstroms, and wherein a thickness of the free layer on the horizontal surface above the flat top of the metal pillar ranges from 3 to 5 angstroms.