The reliability characteristics and thermal conductivity of Ga30Sb70/Sb80Te20 nanocomposite multilayer films were investigated by isothermal resistance and transient thermoreflectance (TTR) measurements, respectively. The crystallization temperature and activation energy for the crystallization can be modulated by varying the layer thickness of Ga30Sb70. A data retention time of ten years of the amorphous state [Ga30Sb70 (3 nm)/Sb80Te20 (5 nm)](13), [Ga30Sb70 (5 nm)/Sb80Te20 (5 nm)](10), and [Ga30Sb70 (10 nm)/Sb80Te20 (5 nm)](7) was estimated when ambient temperature is 137, 163, and 178 degrees C, respectively. Ga30Sb70/Sb80Te20 nanocomposite multilayer films were found to have lower thermal conductivity in both the amorphous and crystalline state compared to Ge2Sb2Te5 film, which will promise lower programming power in the phase-change random access memory. (C) 2011 Elsevier B. V. All rights reserved.