The optimization effect of titanium on the phase change properties of SnSb4 thin films for phase change memory applications

Abstract

Titanium-doped SnSb₄ phase-change thin film has been experimentally investigated for phase-change random access memory (PCRAM) use. The crystallization temperature, amorphous/crystalline resistance, and data retention of the SnSb₄ thin film can be significantly enhanced by doping with titanium, improving the thermal stability of the amorphous state and reducing power consumption. The effect of titanium doping on electrical transport in the thin film was explored using the Hall system. X-ray diffraction and transmission electron microscopy confirmed that the grain size of the thin film was reduced as the titanium content was increased. Grain refinement improved the density changes of the thin films before and after the phase transition. The consequent change in chemical bonding states after adding titanium indicated that Ti was bonded to Sb in the SnSb₄ lattice structure, wrapping around the Sb grains in an amorphous state. PCRAM cells based on Ti_0.10SnSb₄ thin film can be realized with a whole operation window by a 50 ns width pulse, and the operating power consumption was lower than that of a Ge₂Sb₂Te₅ (GST) PCRAM cell of similar dimensions.