Phase Transition Phenomena in Ultra-Thin Ge2Sb2Te5 Film
ZHANG Ting1,3, LIU Bo1, SONG Zhi-Tang1, LIU Wei-Li1, FENG Song-Lin1, CHEN Bomy2
1The Research Center of Functional Semiconductor Film Engineering Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050
2Silicon Storage Technology, Inc. 1171 Sonora Court, Sunnyvale, CA 94086 USA
3Graduate School of the Chinese Academy of Sciences, Beijing 100039
Phase Transition Phenomena in Ultra-Thin Ge2Sb2Te5 Film
1The Research Center of Functional Semiconductor Film Engineering Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050
2Silicon Storage Technology, Inc. 1171 Sonora Court, Sunnyvale, CA 94086 USA
3Graduate School of the Chinese Academy of Sciences, Beijing 100039
Abstract： We observe reversible phase transition phenomena in proto-type chalcogenide random access memory (C-RAM) devices adopting ultra-thin (12nm) Ge2Sb2Te5 thin film. In this kind of proto-type device, the ultra-thin amorphous Ge2Sb2Te5 thin film undergoes a crystallization process when a voltage is applied. The polycrystalline Ge2Sb2Te5 remain unchanged when the voltage is below 0.6V. A higher power is needed if the transition from polycrystalline to amorphous is expected. The re-amorphization process can be realized by applying a voltage higher than 0.7V. The threshold voltage Vth and threshold electric field Eth of the transition from the polycrystalline state to the amorphous state in this proto-type device are ～0.7V and ～5×105V/cm, respectively. The programming voltage is significantly reduced compared to the values of C-RAM devices adopting a 200-nm-thick
Ge2Sb2Te5 inset.
2005, Vol. 22 
