Crystallization-induced stress in phase change random access memory

Abstract

Switched phase change material in Phase Change Random Access Memory (PCRAM) is confined within a solid surrounding. As a result of mechanical properties and micro structure differences between the crystalline and the amorphous phases, strains and stresses are generated and may degrade the performance of PCRAM devices. This paper investigated the crystallization-induced stress in phase change Ge 2Sb 2Te 5 (GST) nano film. The electric-thermal and thermo-mechanical simulation results show that the increases of both of the Young's modulus and Coefficient of Thermal Expansion (CTE) are responsible for the stress generation upon crystallization. The XRD studies correlate the strains and stresses with the lattice deformation in crystalline GST films. © 2009 Materials Research Society.