Thermal characterization and analysis of phase change random access memory

The cross-plane thermal conductivity of $Ge2Sb2Te5$⁠, either in its amorphous state or fcc crystallized state, and titanium nitride (TiN) thin films has been measured at room temperature by the $3ω$ method. These materials are involved in the fabrication of phase change random access memory (PC-RAM), $Ge2Sb2Te5$ and TiN being the PC and pseudoelectrode materials, respectively. The thermal conductivity of insulating $SiO2$ and $ZnS:SiO2$ layers was determined too. Each thermal conductivity measurement was performed by the means of at least two strip widths in order to check both the measurement self-consistency and the measurement accuracy. The performance of PC-RAM cells, i.e., the time needed to reach the melting temperature of the PC material and the cooling speed, has been evaluated as a function of both the measured thermal conductivity of the PC material and the reset current intensity independently of the thermal properties of the pseudoelectrodes by the way of analytical formula. The influence of the thickness and the thermal properties of the pseudoelectrodes on the performances have been determined by numerical simulations.