A Stochastic Perturbative Approach to Design a Defect-Aware Thresholder in the Sense Amplifier of Crossbar Memories
The use of nanowire crossbars to build devices with large storage capabilities is a very promising architectural paradigm for forthcoming nanoscale memory devices. However, this new type of memory devices raises questions regarding how to test their correct operation. In particular, the variability affecting the decoder is expected to make very complex the test of these new devices. In this paper we present a method to simplify the test of these new devices by using a current thresholder to detect badly addressed nanowires. In the proposed method, the thresholder design is based on a stochastic and perturbative model of the current through the nanowires. Thus, the calculated thresholder parameters are robust against technology variation. As our experimental results indicate, the thresholder error probability is initially only ∼ 10−4, which can be also reduced further (up to 60×) by trading-off only 35% area overhead in the memory.