Phase Change Characteristics of InxSb40-xTe60 Chalcogenide Alloy for Phase Change Random Access Memory

Abstract

The InxSb40-xTe60 alloy was selected as a new alternative phase change material for Ge2Sb2Te5 (GST) for phase change random access memory (PRAM). The crystal structure of InxSb40-xTe60 was an alpha(Sb2Te3) rhombohedral (a = b = c, alpha = beta = gamma not equal 90 degrees) single phase with identical lattice parameters in a wide composition range of In (0-28 at. %). The crystallization temperature and melting point of InxSb40-xTe60 were in the ranges of 149-219 degrees C and 608-614 degrees C, respectively, and similar to those of GST. The electric properties of InxSb40-xTe60 with a wide composition range of In contents showed the typical PRAM properties such as current-voltage (I-V), resistance-voltage (R-V), and switching behavior. The reset current of InxSb40-xTe60 decreased with increasing In content and the low power consumption and good retention can be realized by controlling In content. The ratio of the cell resistance and sheet resistance of amorphous InxSb40-xTe60 to those crystalline InxSb40-xTe60 were almost the same as or larger than those of GST. The cycling endurance test of InxSb40-xTe60 with a wide range of In contents showed the comparable results to GST. InxSb40-xTe60 was concluded to be a very promising phase change material for PRAM. (C) 2011 The Japan Society of Applied Physics