Ge2 Sb2 Te5 charge trapping nanoislands with high- k blocking oxides for charge trap memory

Abstract

Charge trap memory capacitors using Ge2 Sb2 Te 5 (GST) nanoislands as charge storage media were fabricated. The GST nanoislands were prepared by plasma-enhanced cyclic chemical vapor deposition on a 6 nm thick tunneling SiO2 layer. A 16 nm thick Al2 O3 or 40 nm thick HfO2 film was used as the blocking oxide (BO). A shift in the flatband voltage in the capacitance-voltage test was achieved when the GST nanoislands were interposed between the SiO2 and BOs, highlighting the feasibility of memory applications. The charges were trapped at the interface between the GST and BOs. Stable charge retention up to 104 s was observed. © 2009 The Electrochemical Society.