Memory module-level testing and error behaviors for phase change memory

Phase change memory (PCM) is a promising technology to solve energy and performance bottlenecks for memory and storage systems. To help understand the reliability characteristics of PCM devices, we present a simple fault model to categorize four types of PCM errors. Based on our proposed fault model, we conduct extensive experiments on real PCM devices at the memory module level. Numerical results uncover many interesting trends in terms of the lifetime of PCM devices and error behaviors. Specifically, PCM lifetime for the memory chips we tested is greater than 14 million cycles, which is much longer than for flash memory devices. In addition, the distributions for four types of errors are quite different. These results can be used for estimating PCM lifetime and for measuring the fabrication quality of individual PCM memory chips.