Influence of phase state, conducting sublayer material and deposition method on mechanical properties and adhesion of Ge2Sb2Te5 thin films

Ge2Sb2Te5 (GST225) thin films are used as a functional element in multilayer cells of phase change random access memory (PCRAM, PCM) and have good prospects in electrically driven tunable reflective metasurfaces and on-chip waveguide devices, including those implemented on a flexible substrate. Knowledge of the mechanical properties of GST225 thin films, their adhesion to conductive layers, and the correct choice of conductive material is critical to the reliable operation of these devices. The present work focuses on the effect of phase change on mechanical parameters such as hardness, Young's modulus and stiffness, as well as on the adhesion of GST225 thin films to various metal sublayers (Al, Ti, TiN, W, Ni). The formation of GST225 films was carried out by vacuum thermal evaporation and DC magnetron sputtering, which made it possible to study layers with different distributions of elements over the thickness. [Display omitted] •The Ge2Sb2Te5 films obtained by the DC magnetron sputtering method have higher values of hardness and Young's modulus.•It has been determined that crystallization of the Ge2Sb2Te5 layer leads to the increase of the hardness (∼7 %).•The Ge2Sb2Te5 layers deposited by the DC magnetron sputtering method have the highest adhesion.