Superlattice-like Sb70Se30/HfO2thin films for high thermal stability and low power consumption phase change memory.

ABSTRACT

We have fabricated Sb70Se30/HfO2superlattice-like structure thin films for phase change memory by magnetron sputtering method, and investigated the effect of the HfO2layer on the crystalline characteristics and phase change behavior of Sb70Se30/HfO2thin films. The experimental results show that as the HfO2thickness increases, the crystallization temperature rises, the data retention capacity increases as well as the band gap widens, which is beneficial for improving the thermal stability and reliability of Sb70Se30/HfO2thin films. It was also found that the HfO2composite layer inhibited the grain growth of the Sb70Se30thin film, reducing the grain size and resulting in a smoother surface. In addition, the volume fluctuation of the Sb70Se30/HfO2thin films changes by only 5.58% between amorphous and crystalline. The threshold and reset voltages of the cell based on Sb70Se30/HfO2thin films are 1.52 V and 2.4 V respectively. We found that the HfO2composite layer plays a significant role in improving thermal stability, refining grain size of Sb70Se30phase change films and reducing device power consumption.