Switching Performance Comparison With Low Switching Energy Due to Initial Temperature Increment in CoFeB/MgO-Based Single and Double Barriers

Spin-transfertorque magnetic random-access memory (STT-MRAM) based on a single-barrier magnetic tunnel junction (SBMTJ) and a double-barrier magnetic tunnel junction (DBMTJ) has evolved along with a low switching current and low energy consumption to obtain a high areal density and a fast switching speed. The increment of initial temperature, T
_in
, in STT-MRAM can achieve low switching energy, E
_SW
. However, this leads to an unavoidable decrease in Δ and switching efficiency. In this paper, SBMTJ and DBMTJ were analyzed in terms of the switching efficiency factor with E
_SW
reduction by increasing the Tin. The switching temperature, T
_SW
, was investigated using a finite-element method simulation. The results show that the DBMTJ(A) and SBMTJ with the same MgO layer thickness of 0.9 nm provide a higher switching current, I
_C
, than the DBMTJ(B) with a MgO layer thickness of 1.3 nm. The T
_SW
in a DBMTJ(A) is higher than that in an SBMTJ, while T
_SW
for a DBMTJ(B) is the smallest because of its low I
_C
. The DBMTJ(A) and DBMTJ(B) can be applied in a higher temperature range than the SBMTJ at a Δ of 40. In addition, the STT efficiency factor, Δ/I
_C0
, for a DBMTJ is better than the factor for an SBMTJ. Although the temperature increment would cause an undesirable reduction in Δ, it can reach a low E
_SW
for the requirement of a fast write access time. Therefore, the control device for increasing the T
_in
in the MTJs is attractive and should be promoted in the advancement of memory technology.