OPTOELECTRONIC INVESTIGATIONS OF Ge2Sb2Te5 FOR PHASE CHANGE MEMORY

Abstract

Crystallization kinetics play an important role in phase change memory application. So for simulation of the crystallization behavior of Ge2Sb2Te5 for optical and electrical phase change memory can be done by using two different modeling approaches. These two models are based on Johnson-Mehl-Avrami-Kolmogorov (JMAK) formalism and classical nucleation theory. JMAK theory is used for calculating the volume fraction of crystallized material under the isothermal condition. We have carried out further investigations using JMAK theory. By using these models the effect of temperature on the volume fraction of transformed material can be observed. The effect of enthalpy of fusion on the crystal nucleation rate shows an interesting result i.e. nucleation rate varies linearly with the enthalpy of fusion, and it is also found that growth of clusters depends on the size of cluster’s radii but after a certain large value of cluster radius, growth rate changes very slowly. In this work, we also simulated the resistance versus power per unit volume for both optical (laser power) and electrical power and compare the switching power required for phase transformation from amorphous to crystalline for Ge2Sb2Te5 material. For analysis and simulation, MATLAB is used extensively.