Improvement in stability of GST PCMs on Sm addition for memory devices

Abstract The phase change materials (PCM) are recognized for their use in optical and electrical memory devices. The stability of phase change control depends on the effective alteration of structural configurations. The structural transitions of Ge2Sb2Te5 (GST) PCM on Samarium (Sm) addition are investigated. The possibility of structural units to attain various configurations on Sm addition and their stability are theoretically analysed using the negative correlation energy barrier. The phase change phenomenon of Sm added GST is explained through the bond alternation mechanism. The criterion for the structural modification efficiency (CSME) is calculated from metallicity (M) values. The increase in the values of M and CSME signifies an increase in the rigidity of the network and the possibility of formation of various structural configurations during phase transition respectively. The threshold switching voltage is calculated and found to increase on Sm addition to GST indicating faster crystallization speed for efficient storage applications.