US 12,446,232 B2
MRAM-based chip identification with free random programming
Kangguo Cheng, Schenectady, NY (US); Dimitri Houssameddine, Sunnyvale, CA (US); Julien Frougier, Albany, NY (US); and Ruilong Xie, Niskayuna, NY (US)
Assigned to International Business Machines Corporation, Armonk, NY (US)
Filed by International Business Machines Corporation, Armonk, NY (US)
Filed on May 25, 2021, as Appl. No. 17/329,824.
Prior Publication US 2022/0384367 A1, Dec. 1, 2022
Int. Cl. H10B 61/00 (2023.01); H01L 23/00 (2006.01); H10N 50/80 (2023.01)
CPC H10B 61/10 (2023.02) [H01L 23/573 (2013.01); H10B 61/22 (2023.02); H10N 50/80 (2023.02)] 18 Claims
OG exemplary drawing
 
1. A magnetoresistive random access memory (MRAM) device comprising:
a stack of, from bottom to top, a magnetic via structure and a first electrode;
a first interconnect dielectric material layer embedding both the magnetic via structure and the first electrode;
a magnetic tunnel junction (MTJ) structure located on the first electrode of the stack, wherein the MTJ structure comprises a tunnel barrier layer sandwiched between a magnetic free layer and a magnetic reference layer; and
a second electrode located on the MTJ structure, wherein the magnetic free layer of the MTJ structure has a magnetization vector aligned in a same direction as a magnetization vector of the magnetic via structure, the direction of the magnetization vector of the magnetic via structure is random and is dependent on an aspect ratio of the magnetic via structure and a distance between the magnetic via structure and the magnetic free layer, and the magnetic reference layer has a magnetization vector that can be in the same direction as, or a different direction than, the magnetization vector of both the magnetic free layer and the magnetic via structure, and wherein a read out of the magnetization vectors provides chip identification to a chip containing the MRAM device, wherein the aspect ratio of the magnetic via structure is greater than 2:1 and the distance between the magnetic via structure and the magnetic free layer is no more than 30 nm.