Phase-dependent thermal conductivity of Ge1Sb4Te7 and N:Ge1Sb4Te7 for phase change memory applications

Abstract

We report the thermal conductivities of Ge1Sb4Te7 and nitrogen-doped Ge1Sb4Te7 thin films at temperatures ranging from 300 to 520 K using the 3ω method. Thermal conductivity of Ge1Sb4Te7 increases abruptly during the transition from the amorphous to crystalline phase. Nitrogen doping effectively suppresses the crystallization process, resulting reduction of lattice as well as electronic thermal conductivity. These behaviors are confirmed by x-ray diffraction, sheet conductance, and thermal conductivity measurements. Numerical modeling of phase change memory device shows that with nitrogen doping, performance increase in terms of lower reset current and faster reset time can be achieved.