LAUSR

Phase change memory (PCM) is regarded as a promising technology for storage- class memory and neuromorphic computing, owing to the excellent performances in operation speed, data retention, endurance, and the controllable crystallization dynamics, whereas the high-power consumption of PCM remains to be a short-board characteristic that limits its extensive applications. Here, Sc doped Bi0.5Sb1.5Te3 has been proposed for high-speed and low-power PCM application. The operation speed of 6 ns and the threshold current of 0.7 mA has been achieved in 190-nm Sc0.23Bi0.5Sb1.5Te3 PCM, which consumes a lower power than those of GeSbTe and ScSbTe PCM. A good endurance of 5×105 has been achieved, attributed to the small volume change of 4% during phase change and good homogeneity phase in crystalline state. The structure of amorphous Sc0.23Bi0.5Sb1.5Te3 has been characterized by experimental and theoretical methods, showing the existence of large amount of the crystal-like structural factions, that can efficiently minimize the atomic movements required for crystallization, and subsequentially improve the operation speed and power efficiency. The low diffusivity of Sc and Bi at room temperature, and the rapidly increased diffusivity of Bi at elevated temperature, are fundamental for the high data retention of 94 °C and the fast crystallization in Sc0.23Bi0.5Sb1.5Te3. The combination of the high atomic mobility and the minimized atomic movements during crystallization ensures the high speed and the low power consumption of Sc0.23Bi0.5Sb1.5Te3 PCM, that can promote its application to the energy-efficient systems, i.e. AI chips and wearable electronics.