A Code Inversion Encoding Technique to Improve Read Margin of A Cross-Point Phase Change Memory

In this paper, we propose a code inversion encoding technique to improve the read margin of a cross-point phase change memory (PCM). The proposed technique reduces the maximum number of low resistance state cells which significantly reduce read margin by increasing sneak current. Therefore, the proposed scheme can significantly improve the read margin of the cross-point PCM. To verify the improvement of read margin by the proposed technique, we simulated and compared read margins of various arrays with and without the proposed technique. According to the simulation, our technique improves the read margin by 102% or equivalently allows to increase the array size by 91.6% without decreasing for the read margin. The results show that the proposed technique greatly improves the read margin.