A study on the crystallization behavior of nitrogen doped Ge ₂Sb₂Te₅ thin film

We investigated the crystallization behaviors of nitrogen doped Ge ₂Sb₂Te₅ thin films deposited in various nitrogen gas flow rates by means of the 4-point probe technique, X-ray diffraction and transmission electron microscopy (TEM), and we mapped the change of crystallization behavior on annealing temperatures. Nitrogen doping resulted in an increase of crystallization temperature from amorphous to fcc structure and maintained the fcc structure up to a higher annealing temperature than un-doped film did. However, crystallization behavior in heavily nitrogen-doped film occurred from an amorphous directly to a hexagonal state, skipping the fee crystallization step.