Fabrication and performance analysis of TiN/W superlattice electrodes for low-power phase change memory

High thermal conductivity of electrode materials in Phase Change Memory (PCM) is one of the reasons for the power consumption during the reset process. How to effectively reduce the thermal conductivity of electrode materials is of great significance to the development of low-power PCM. In order to obtain metal electrodes with low thermal conductivity, superlattice structures were fabricated on silicon substrate by magnetron sputtering based on two common electrode materials of PCM, Titanium Nitride (TiN) and Tungsten (W). The period of TiN/W superlattice is 6, and the thickness of single-layer is designed to be 10nm and 5nm respectively. The cross section SEM images of the two samples indicates that the interface between layers is clear and the total thickness of the two samples is 123nm and 64nm respectively. Thermal conductivity is characterized as 1.682W/$\mathrm{m}\cdot\mathrm{K}$ and 0.721W/$\mathrm{m}\cdot\mathrm{K}$ respectively by 30) method, which is much lower than the bulk thermal conductivity of TiN and W. In addition, the thermal field distribution of Reset process of PCM was simulated. The results show that the fabricated superlattice electrode can confine the heat inside the PCM better and resulting in a 13% reduction in the voltage required for the Reset process compared with the traditional electrode with single-layer W. In summary, TiN/W superlattice electrodes with low thermal conductivity were successfully fabricated by magnetron sputtering, which is profit to reduce the power consumption for PCM.