The effect of Ta interface on the crystallization of amorphous phase change material thin films

摘要

The crystallization of amorphous GeTe and Ge_2Sb_2Te_5 phase change material films, with thickness between 10 and 100 nm, sandwiched between either Ta or SiO_2 layers, was investigated by optical reflectivity. Ta cladding layers were found to increase the crystallization temperature, even for films as thick as 100 nm. X-Ray diffraction investigations of crystallized GeTe films showed a very weak texture in Ta cladded films, in contrast with the strong texture observed for SiO_2 cladding layers. This study shows that crystallization mechanism of phase change materials can be highly impacted by interface effects, even for relatively thick films.