Structural and compositional evolution of carbon-doped Ge2Sb2Te5 film under different annealing conditions

Changes in the microstructural and electrical properties of carbon-doped Ge2Sb2Te5 during thermal annealing under N2 and air atmospheres are investigated. The occurrence of compositional and structural changes was found to depend on the annealing conditions, and in particular, on the out-diffusion of germanium atoms. The thick oxidation layer generated during air annealing prevented germanium out-diffusion, leading to structural changes but no compositional changes. In contrast, germanium out-diffusion occurred during annealing under N2, leading to compositional changes but preventing structural changes.