Improved phase-change characteristics of Si doped GeSbTe thin films used for phase change memory

Abstract The phase-change characteristics of silicon doped Ge 2 Sb 2 Te 5 (Si-GST) film were investigated and compared with pure Ge 2 Sb 2 Te 5 (GST) film. The results of in situ temperature dependence of the sheet resistance demonstrate that the crystalline resistivity of GST film increased by the silicon doping, but the phase transition temperature T c was almost unchanged. The minimum on/off ratio for Si-doped GST is around 240, which is high enough to be used for device application. Both of the GST and Si-doped GST prototype memory devices can perform SET and RESET cycles. The threshold voltage V th increased while the RESET current decreased with silicon doping. Applying the Kissinger method the activation energy for crystallization of Si-doped GST film (300 nm) is determined to be 2.30 ± 0.05 eV.