Effects of Ca doping on the crystallization kinetics of GeTe

Doping is an effective way to improve the performance of conventional phase-change materials. We introduced an alkaline element calcium (Ca) in GeTe films and studied their crystallization kinetics by using flash DSC. It was found that a small amount of Ca doping (4.0 at. %) can significantly enhance the thermal stability, but the maximum crystal growth rate does not decrease significantly. Moreover, no any Ca-related crystalline phase and Ca-related chemical bond can be found in Ca-doped GeTe, implying that Ca atoms are in free state in GeTe matrix.