Study on the Resistance Drift in Amorphous Ge2Sb2Te5 According to Defect Annihilation and Stress Relaxation

Abstract

Time-dependent drift of resistance in chalcogenide glasses leads to instabilities in phase-change random access memory (PCRAM). To reveal the origin of the resistance drift, mechanical stress relaxation and electrical resistance measurements were conducted on amorphous Ge2Sb2Te5 thin films under the same sample conditions. Resistance drift follows a power-law relationship with time, which is different from the trend observed for stress relaxation. The models that enable the time-dependence of resistance to be calculated from stress relaxation have been proposed and the calculated resistances were compared to the measured resistance. Our results show that the defect annihilation explains the drift phenomena successfully.