Scaling analysis of in-plane and perpendicular anisotropy magnetic tunnel junctions using a physics-based model

Comprehensive Scaling Analysis of Current Induced Switching in Magnetic Memories Based on In-Plane and Perpendicular Anisotropies

“…Write-currents are thus Table I. indicative of the write failures. We chose a WER of 7.95e-7 [7] and a switching time of 4 ns for our analysis (without loss of generality). To obtain realistic results, we have chosen material parameters from experimental data, summarized in Table I.…”

“…were selected for a retention time of 10 years. The chosen (mentioned in Table II) have been adopted from [7] where authors estimated for L3 cache assuming a retention time of 10 years. The details of calculations based on failure rates and retention time can be found in [7].…”

“…In [6], for example, the authors presented scaling trends based on analytical solutions to equations describing magnetization dynamics. In [7], the authors used a more realistic approach by numeri- Fig. 2.…”

“…The analysis in [7] was with respect to the write current requirements for STT-MRAMs. Novel cell structures as in [8] have been proposed for better reliability at scaled technology nodes.…”

Magnetic Tunnel Junctions and Their Applications in Nonvolatile Circuits

“…14, it is clear that, in principle, perpendicular MTJ devices, independent of their size, will require an approximately constant switching current I c0 once the target for D is established based on the requirements for the MTJ in the nonvolatile circuit. This presents a fundamental problem for the scaling trend of perpendicular MTJ devices, as the transistors needed to drive this constant switching current will not significantly shrink with successive technology nodes [61][62][63], hence limiting the possibility to scale the transistors of the nonvolatile circuits and making the circuit area possibly constrained by the area of the transistors instead of the NVM element. However, a recent work by Sato et al [64] experimentally Handbook of Spintronics DOI 10.1007/978-94-007-7604-3_42-1 # Springer Science+Business Media Dordrecht 2015 studying the scaling of I c0 and D on devices down to 11 nm shows that, even though the scaling trend predicted in section "Perpendicular MTJ Devices" is accurately followed for D in perpendicular MTJ devices below $30 nm, the figure of merit I c0 /D is experimentally observed to decrease as the device shrinks, which may be attributed to the reduction of the effective damping in Eq.…”