Influence of interfaces on the crystallization characteristics of Ge2Sb2Te5

The crystallization times (τ_x) and crystallization temperatures (T_x) of the phase change material Ge₂Sb₂Te₅ (GST) as a function of capping materials was systemically evaluated. SiO₂ and GeO_x capping materials accelerated the recrystallization of 10nm GST substantially and increased T_x. In addition, the crystallization mechanisms depended on GST thickness as well as capping materials. For very thin films, T_x increased by up to 120°C and re-crystallization times were shortened. Through optimization of phase-change layer thickness and interface conditions, a material system with faster recrystallization time and with higher thermal stability is proposed, which is promising for the scalability of phase change random access memory technology.