Phase and thickness dependent modulus of Ge2Sb2Te5 films down to 25 nm thickness

The mechanical properties of phase-change materials including Ge2Sb2Te5 (GST) are strongly influenced by the complex interaction of phase and imperfection distributions, especially at film thicknesses relevant for phase-change memory devices. This work uses a micromechanical resonator as a substrate to study the phase dependent modulus of GST films with thicknesses from 25 nm to 350 nm. The moduli of amorphous GST and crystalline GST films increase with decreasing thickness to 10 GPa and up to 60 GPa, respectively. The phase purity is studied using X-ray diffraction and energy dissipation data, which provide qualitative information about inelastic absorption. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3699227]