Elastic modulus of amorphous Ge₂Sb₂Te₅ thin film measured by uniaxial microtensile test

The elastic property of an amorphous Ge₂Sb₂Te₅ thin film was investigated by uniaxial microtensile test using amorphous Ge₂Sb₂Te₅ films deposited on both sides of a polyimide substrate. The elastic modulus of the amorphous Ge₂Sb₂Te₅ thin film was determined by the rule of mixture as 20.2 ± 1.3 GPa, comparable to that converted from the biaxial modulus measured by wafer curvature measurements. However, the elastic modulus measured by nanoindentation tests is higher than those measured by uniaxial microtensile test and by wafer curvature measurements, as the viscoelastic recovery component of the amorphous Ge₂Sb₂Te₅ film is not implied in the initial slope of the unloading curve in nanoindentation tests.