High-density phase change material (PCM) array is considered to be an efficient method to decrease operation voltage
and power of phase change random access memory (PCRAM). In the paper, the Si<sub>2</sub>Sb<sub>2</sub>Te<sub>5</sub> (SST) array was fabricated by
UV-imprint lithography (UV-IL) and the memory array with 18M/Inch<sup>2</sup> were constructed. Structural transformation of
SST film in heating process was in situ studied by using time-resolved X-ray diffraction. The threshold current and
threshold voltage for SST based memory cell are 9.9μA and 0.23V, respectively. After 20ns pulse width inspired,
Set/Reset switching operation was achieved and the resistance ratio reached 34. The results show that the SST have
potential application in the low-voltage, high-speed storage. The outstanding performance of SST and the new structure
enables it to become the new storage devices.