Revisiting the Crystallization Model of Phase Change Memory with Ab Initio Simulations

The crystallization of phase change memories (PCM) is usually described by a Johnson-Mehl-Avrami(JMA) equation in a SPICE model. In this work recent ab initio molecular dynamic simulation results are used for the JMA equation benchmark. It is found that: (a) the commonly used JMA equation does not account for the incubation period at the initial stage of phase change memory crystallization, even the equation is easily implemented with a sub-circuit. (b) the JMA equation based on the Arrhenius formula cannot reflect the crystallization rate with temperature. This paper proposes a crystallization model that can reproduce the incubation period and the crystallization rate dependence on temperature, thus improves the model accuracy.