Sputter-grown GeTe/Sb2Te3 superlattice interfacial phase change memory for low power and multi-level-cell operation

Abstract

The multi-level feature of GeTe/Sb2Te3 interfacial phase change memory was achieved by applying a designed voltage-based pulse. It stably demonstrated five multi-level states without interference for 90 cycles by varying the pulse width. GeTe/Sb2Te3 interfacial phase change memory demonstrated retention time of > 1.0 × 103 s, presenting the significantly low drift coefficient (ν) of < 0.009, indicating no resistivity drift due to the structure relaxation of glass. In addition, the reset energy consumption of GeTe/Sb2Te3 interfacial phase change memory was reduced by more than 85% compared to conventional Ge2Sb2Te5 phase change memory at each bottom electrode contact size. Multi-level-cell operation mechanism and gradual increase in conductance value of GeTe/Sb2Te3 interfacial phase change memory was explained by a partial resistance transition model where phase transition occurred partially in all layers. The result of the GeTe/Sb2Te3 interfacial phase change memory performance is expected to bring great advantages to the next-generation storage class memory industry that requires low energy and high density.