US 12,431,214 B2
External magnetic field detection for MRAM device
Harry-Hak-Lay Chuang, Zhubei (TW); Yuan-Jen Lee, Hsinchu (TW); Tien-Wei Chiang, Taipei (TW); and Yi-Chun Shih, Taipei (TW)
Assigned to Taiwan Semiconductor Manufacturing Company, Ltd., Hsinchu (TW)
Filed by Taiwan Semiconductor Manufacturing Company, Ltd., Hsinchu (TW)
Filed on Apr. 20, 2022, as Appl. No. 17/724,963.
Claims priority of provisional application 63/294,527, filed on Dec. 29, 2021.
Prior Publication US 2023/0207045 A1, Jun. 29, 2023
Int. Cl. G11C 29/52 (2006.01); G06F 11/10 (2006.01); G11C 11/16 (2006.01); H10B 61/00 (2023.01)
CPC G11C 29/52 (2013.01) [G06F 11/1044 (2013.01); G11C 11/161 (2013.01); G11C 11/1673 (2013.01); G11C 11/1675 (2013.01); G11C 11/1677 (2013.01); H10B 61/22 (2023.02)] 20 Claims
OG exemplary drawing
 
1. A magnetoresistive random access memory (MRAM) device comprising:
a main magnetic tunnel junction (MTJ) array comprising a plurality of memory cells configured to store memory data;
a reference MTJ array comprising a plurality of reference cells including a first reference cell and a second reference cell coupled in series and having MTJ structures, wherein the first and second reference cells have a first resistance when the MTJ structures of the first and second reference cells have a first magnetization orientation, wherein the first and second reference cells have a second resistance, greater than the first resistance, when the MTJ structures of the first and second reference cells have a second magnetization orientation different than the first magnetization orientation, and wherein a gross resistance of the reference MTJ array includes a resistance of the first reference cell and a resistance of the second reference cell and is related to a strength of an external magnetic field around the MRAM device; and
a controller operatively associated with the main MTJ array and the reference MTJ array, wherein the controller is configured to:
initialize the resistance of the first reference cell and the resistance of the second reference cell to the second resistance to initialize the gross resistance of the reference MTJ array to a third resistance, greater than the second resistance;
receive the gross resistance of the reference MTJ array;
determine whether the gross resistance of the reference MTJ array is less than a pre-determined threshold;
determine that at least a portion of the memory data stored in the main MTJ array is unrepairable in response to determining that the gross resistance of the reference MTJ array is less than the pre-determined threshold; and
provide notification indicating that the memory data stored in the main MTJ array is untrustworthy in response to determining that at least the portion of the memory data stored in the main MTJ array is unrepairable.