High speed and low power consumption of superlattice-like Ge/Sb70Se30 thin films for phase change memory application

In comparison to Ge2Sb2Te5 (GST) and pure Sb70Se30 (SbSe) thin films, superlattice-like (SLL) Ge/Sb70Se30 (Ge/SbSe) has a higher crystallization temperature, larger crystallization activation energy, better data retention and lower power consumption. SLL Ge/SbSe thin films with different thickness of Ge and SbSe layers were prepared by magnetron sputtering system. The amorphous-to-crystalline transitions of SLL Ge/SbSe thin films were investigated through in situ film resistance measurement. The crystallization activation energy of SLL Ge/SbSe thin films was calculated from a Kissinger plot. The data retention time was estimated through isothermal time-dependent resistance measurement by Arrhenius equation. The phase structure of the thin films annealed at different temperatures was investigated by using X-ray diffraction. Phase change memory cells based on the SLL [Ge(8 nm)/SbSe(5 nm)]4 thin films were fabricated to test and evaluate the switching speed and operation consumption.