Macro model for stochastic behavior of resistance distribution of magnetic tunnel junction

Abstract

In this work, we fabricated MgO-based magnetic tunnel junction (MTJ) samples to observe behavior of resistance variation, and investigated a stochastic behavior model for MTJ resistance from measured real data. We found the relationship between parallel resistance (R-P), anti-parallel resistance (R-AP), and TMR from the measurements. The variation of barrier thickness affects not only resistance but also TMR. This means that broad R-AP distribution is caused by R-P distribution. In addition, R-AP distribution can be reduced by increasing temperature and bias voltage. We developed a macro model that can evaluate resistance distribution based on the stochastic behavior of MTJ resistance variation from only t(ox) varied. The amount of resistance variation, which is considered with regard to the circuit performance, can be obtained from Delta(tox) designed by designer. In addition, the impact for operating circumstance such as bias and temperature can be considered by using fit equations.