SiO₂ doped Ge₂Sb₂Te₅ thin films with high thermal efficiency for applications in phase change random access memory

This study examined the various physical, structural and electrical properties of SiO₂ doped Ge₂Sb₂Te₅ (SGST) films for phase change random access memory applications. Interestingly, SGST had a layered structure (LS) resulting from the inhomogeneous distribution of SiO₂ after annealing. The physical parameters able to affect the reset current of phase change memory (I_res) were predicted from the Joule heating and heat conservation equations. When SiO₂ was doped into GST, thermal conductivity largely decreased by ∼ 55%. The influence of SiO₂-doping on I_res was examined using the test phase change memory cell. I_res was reduced by ∼ 45%. An electro-thermal simulation showed that the reduced thermal conductivity contributes to the improvement of cell efficiency as well as the reduction of I_res, while the increased dynamic resistance contributes only to the latter. The formation and presence of the LS thermal conductivity in the set state test cell after repeated switching was confirmed.