Thickness dependent nano-crystallization in Ti0.43Sb2Te3 films and its effect on devices

The crystallization behavior of ultrathin Ti0.43Sb2Te3 (TST) films dependent on thickness was studied. As the film thickness decreases, the crystallization temperature (Tc) firstly increases in the thickness range of 10-50 nm, and then decreases when the thickness is less than 10 nm. Two factors can explain the variation trend of Tc with decreasing thickness of TST films. The increment of Tc is mainly due to the crystallization suppression originating from the increment of surface-to-volume in 10-50 nm TST films, and the decrement is dominantly attributed to the crystallization promoter of substrate/film interface in sub-10 nm TST films. The current-voltage and resistance-voltage measurements of 50 nm-TST-based and 10 nm-TST-based devices exhibit that 10 nm-TST-based device can realize low voltage and low power operation, but owns relatively lower speed for its longer incubation time.