Multi-Step Resistance Memory Behavior in Ge₂Sb₂Te₅/GeTe Stacked Chalcogenide Films

Abstract

The multi-step resistance behavior was observed in the Ge₂Sb₂Te₅/GeTe bistratal stacked films investigated by utilizing in situ temperature-dependent film resistance measurements. The [Ge₂Sb₂Te₅ (30 nm)/GeTe (70 nm)] stacked films had a larger resistance difference among different resistance states. The data retention temperatures for 10 years of amorphous and intermediate states of [Ge₂Sb₂Te₅ (30 nm)/GeTe (70 nm)] films were estimated to be 126°C and 166°C, respectively. X-Ray Diffractomer revealed the changes of phase structure in Ge₂Sb₂Te₅/GeTe bistratal stacked films with different annealing temperature. Theoretical simulation of the temperature distribution of the PCM cell with bistratal films was used to examine the multi-step switching mechanism.

Keywords:

• Stacked films
• multi-step resistance memory
• data retention
• phase-change random access memory
• theoretical simulation

Acknowledgments

The authors would like to acknowledge financial support of the Foundation Project by Science and Technology Council of Shanghai (Grant No. 1052 nm 07200) and the National High Technology Development Program of China (2008AA031402).