Structural Evolution of Amorphous Ge 2 Sb 2 Te 5 Thin Films in the Transition to the Crystalline Phase

The crystallization kinetics of as-deposited amorphous Ge 2 Sb 2 Te 5 thin films has been measured by in situ time resolved reflectivity. X-ray diffraction and Raman scattering analyses of partially transformed samples allowed to correlate the evolution of the transition to the structural modification in the long and short range configuration. The experimental results evidenced that during the early stages of crystallization there is a reduction of Ge-Te tetrahedral bonds, characteristics of the Ge coordination in amorphous Ge 2 Sb 2 Te 5 films.