Voltage-control spintronics memory (VoCSM) with low write current using highly-selective patterning process

A voltage-control spintronics memory (VoCSM) which has a potential of low energy consumption uses the spin-Hall effect (SHE) and the voltage-controlled magnetic anisotropy (VCMA) effect for its write operation. In this work, the relationship between the critical switching current (Ic _sw ) and the SHE electrode thickness (t _N ) is investigated in the range of 5 nm < t _N < 8 nm. In the fabrication process, we develop highly-selective patterning process to stop MTJ etching precisely on the surface of the SHE electrode. Using the technique, Ic _sw is reduced by half as t _N is varied from 8 nm to 5 nm, and Ic _sw of 112 mA at 20 ns write current pulse is obtained for MTJ size of 50 × 150 nm ² on Ta(2 nm)/TaB (3 nm) electrode. The results indicate that the decrease in the SHE electrode thickness is a promised method to reduce Ic _sw, which leads VoCSM to a low-energy-consumption device.