Ultrafast switching in nanoscale phase-change random access memory with superlattice-like structures

作者：Loke Desmond; Shi Luping^*; Wang Weijie; Zhao Rong; Yang Hongxin; Ng Lung Tat; Lim Kian Guan; Chong Tow Chong; Yeo Yee Chia

来源：Nanotechnology, 2011, 22(25): 254019.

DOI：10.1088/0957-4484/22/25/254019

Phase-change random access memory cells with superlattice-like (SLL) GeTe/Sb2Te3 were demonstrated to have excellent scaling performance in terms of switching speed and operating voltage. In this study, the correlations between the cell size, switching speed and operating voltage of the SLL cells were identified and investigated. We found that small SLL cells can achieve faster switching speed and lower operating voltage compared to the large SLL cells. Fast amorphization and crystallization of 300 ps and 1 ns were achieved in the 40 nm SLL cells, respectively, both significantly faster than those observed in the Ge2Sb2Te5 (GST) cells of the same cell size. 40 nm SLL cells were found to switch with low amorphization voltage of 0.9 V when pulse-widths of 5 ns were employed, which is much lower than the 1.6 V required by the GST cells of the same cell size. These effects can be attributed to the fast heterogeneous crystallization, low thermal conductivity and high resistivity of the SLL structures. Nanoscale PCRAM with SLL structure promises applications in high speed and low power memory devices.

• 出版日期2011-6-24