Phase transitions in Ge-Te phase change materials studied by time-resolved x-ray diffraction

Resistivity versus temperature measurements and time-resolved x-ray diffraction were used to study Ge-Te phase change materials. Resistivity versus temperature measurements showed one sharp drop in resistivity for films with 30, 50, and 70 at. % Ge, two steps for films with 40 at. % Ge, and a gradual transition for films with 60 at. % Ge. Films with 30, 50, and 70 at. % Ge crystallized in a single-step process with GeTe and Te, only GeTe, and GeTe and Ge diffraction peaks, respectively. Films with 40 and 60 at. % Ge crystallized in a two-step process with GeTe peaks appearing first and additional Te or Ge peaks, respectively, appearing at higher temperature. © 2009 American Institute of Physics.