Thermal conductivity measurements and modeling of phase-change GE ₂SB₂TE₅ materials

Phase-change technology has been widely used in rewritable disks for optical recording applications. Recently, it has also received attention as a candidate for future high-storage-density nonvolatile random access memory, due to its much longer cycle life (̃10¹³) and fast data access time (̃100 ns) compared with the existing flash memory technology. In this article, we present thermal conductivity data and models for phase-change GeSbTe material that would be helpful in performance optimization and improvement in the reliability of phase change-based data storage devices and systems. We present thermal conductivity data for a 40-nm-thick Ge2Sb2Te5 phase-change layer in both amorphous and crystalline states using electrical resistance joule heating and thermometry techniques. The limits of lattice and electronic thermal conductivities are investigated to determine their relative contributions to the total thermal conductivity as a function of tellurium concentration, crystalline structures, and temperature.