Voltage acceleration and pulse dependence of barrier breakdown in MgO based magnetic tunnel junctions

STT-MRAM is a promising non-volatile memory. For reliable lifetime predictions, a correct voltage acceleration model is essential. However, there is no consensus over what acceleration model to use. In this paper we study barrier breakdown time over an extended time range. With a maximum likelihood ratio method, we test the statistical significance of fits for different voltage acceleration models. We find that the power law best describes voltage acceleration. In addition we observe that the breakdown time is independent of duty cycle or pulse width.