SPIN-ORBIT TORQUE MAGNETIC RANDOM ACCESS MEMORY

專利類型

發明

專利國別 (專利申請國家)

美國

專利申請案號

15/435,547

專利證號

US 9,929,210

專利獲證名稱

SPIN-ORBIT TORQUE MAGNETIC RANDOM ACCESS MEMORY

專利所屬機關 (申請機關)

國立清華大學

獲證日期

2018/03/27

技術說明

一種具熱穩定性之 SOT-MRAM，包含基板及設置於基板並具一磁性自由層的自旋軌道扭力式記憶胞。磁性自由層包括鐵磁性的第一金屬膜、接觸第一金屬膜且分別呈反鐵磁性與自旋霍爾效應的第二、三金屬膜。第一金屬膜具介於 0.5nm 至 1.5nm 間的第一厚度。第二金屬膜具一足以對磁性自由層提供有一交換偏移場( )且大於 6nm 的第二厚度。 是在沿第一金屬膜之難軸對磁性自由層同時提供有外加磁場及交流脈衝電訊號以達交流脈衝電訊號所產生之臨界電流密度時所形成。第二金屬膜是未經垂直場退火與非經垂直場鍍膜所構成的IrMn 合金膜。磁性自由層本質上在達臨界電流密度時具一矯頑場(Hc)，且 |H¬EB| > |Hc|。 A spin-orbit torque magnetic random access memory (SOT-MRAM) includes a substrate and an SOT memory cell. The SOT memory cell is disposed on the substrate and includes a magnetic free layer. The magnetic free layer includes a ferromagnetic first metal layer, an anti- ferromagnetic second metal layer contacting the first metal layer, and a third metal layer contacting the first metal layer for generating the spin-Hall effect. The first metal layer has a thickness ranging from 0.5 nm to 1.5 nm and exhibits perpendicular magnetic anisotropy. The second metal layer has a thickness of greater than 6 nm for providing an exchange bias field (HEB) upon an external magnetic field and an electric pulse, which are provided along a hard axis of the first metal layer, reaching a critical current density. The second metal layer is an IrMn layer which is not undergone out-of-plane magnetic annealing or out-of-plane magnetic coating and exhibits no perpendicular magnetic anisotropy. The magnetic free layer has a coercive magnetic field (Hc) upon reaching the critical current density, and |H¬EB| > |Hc|.

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