Ga doping induced thermal stabilization of fcc phase in Ge2Sb2Te5 thin films: A step toward power-efficient phase change memories.

Ge 2 Sb 2 Te 5 (GST), a phase change material, generally exhibits two-step crystallization (amorphous → fcc → hcp) to store and process data. The present study reports the crystallization behavior and bonding mechanism of Ga-doped GST thin films with thermal annealing. Ga doping results in the formation of Ga–Te bonds and shows no bonding with other host elements (Ge and Sb), which changes the bonding mechanism and leads to one-step crystallization (amorphous → fcc). The optical transmission contrast confirmed the thermal stabilization of the fcc phase with thermal annealing. These findings suggest that Ga doping into GST thin films has thermally stabilized the metastable fcc phase and suppressed the hcp phase, hence posing it as a potential candidate for phase change memory applications with fast processing speed and low power consumption. [ABSTRACT FROM AUTHOR]