Ge2Sb2Te5 Charge Trapping Nanoislands with High-k Blocking Oxides for Charge Trap Memory

Charge trap memory capacitors using Ge2Sb2Te5 (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 Al2O3 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 10(4) s was observed. (C) 2009 The Electrochemical Society. [DOI: 10.1149/1.3195078] All rights reserved.