Kinetics features of 2D confined Ge2Sb2Te5 ultrathin film

Ge2Sb2Te5 (GST) films of 7 nm thickness in the multilayer structure of [GST 7 nm/W 6 nm]20 have been fabricated, and their crystallization kinetics is studied via ultrafast differential scanning calorimetry and a generalized Mauro–Yue–Ellison–Gupta–Allan viscosity model. A distinct fragile-to-strong crossover (FSC) transition behavior, which is beneficial to balance the contradiction between good thermal stability nearby glass transition temperature Tg and fast crystal crystallization speed around melting temperature, is found in this 2D confined GST ultrathin film with the FSC transition temperature of 1.25 Tg. The above analyses are helpful to understand the kinetics features of an ultrathin GST material in a low-dimensional phase-change device for neuro-inspired in-memory computing.