Configuration effects of superlattice‐like phase change material structure

Superlattice-like (SLL) structure has been proposed to manipulate phase change materials' properties and applied in phase change random access memory to not only reduce programming current but also overcome the trade-off between crystallization speed and stability. This work investigated the effect of two SLL stack configurations, pair and sandwich structures, on the memory cell. The SLL component phase change material with fast crystallization speed was selected to be deposited first on the bottom electrode. It was found that cell performance was highly dependent on the SLL stack structure. In particular, cell with sandwich SLL structure exhibited the lowest RESET current comparing with cell with pair SLL or single Ge2Sb2Te5 layer. In addition, the evolution of the electrical behavior against the lifetime and IV characterization measurement showed that sandwich SLL structure possessed better endurance and thermal stability. The possible mechanisms to induce the differences are discussed. These findings enable to exploit phase change materials by structural engineering to meet the requirements of different applications.