Large-area, scalable fabrication of conical TiN/GST/TiN nanoarray for low-power phase change memory

We demonstrate the fabrication and phase change memory performance of a conical TiN/Ge ₂Sb ₂Te ₅ (GST)/TiN nanoarray prepared via block copolymer lithography and straightforward two-step etching. The created 30 nm scale phase change memory cell (aerial array density: ∼207 Gbit inch ^-2) showed a threshold switching voltage of 1.1 V, a value compatible to conventional phase change memory cells. More significantly, the cell could be amorphized by a reset pulse of 1.8 V height and 100 ns width, where the reset current was 100 μA. Such a low reset current, presumably caused by nanoscale small cell dimension, is greatly beneficial for low power consumption device operation. Reversibly, the set operation was accomplished by crystallization with a set pulse of 1.2 V height, 100 ns width, and 100 ns trailing. This work provides a significant step for low power consumption and ultra-high density storage based on phase change materials.