Four nm thick TiN film was inserted between Sb2Te3 and Ge2Sb2Te5 films in conventional doublelayer phase change memory cell. The novel sandwich-structure phase change memory cell was still able to show triple level data storage ability. Interdiffusion between Sb2Te3 and Ge2Sb2Te5 films is suppressed by this TiN layer. Compared with conventional doublelayer phase change memory cell, smooth resistance stages with more consistent resistance magnitudes and better data endurance characteristics of all resistance states have been achieved on the sandwich-structure phase change memory cell. (C) 2008 Elsevier Ltd. All rights reserved.