Temperature dependent interfacial adhesion strength between phase change material film and a SiO₂ layer was investigated employing Nano Indenter^®. Phase change materials of Ge₂Sb₂Te₅ and Si₂Sb₂Te₆ were adopted for a comparative study. The decrease of adhesive strength with an increased annealing temperature can be deduced from the optical micrographs of the two cases. Critical load obtained from the nanoscratch tests was introduced to quantitative characterize the interfacial adhesion strength of the samples. Scanning electron microscope and energy dispersive spectrometer were utilized to further analysis the adhesive properties of the interfaces. Results show that Si₂Sb₂Te₆ has better adhesive performance than Ge₂Sb₂Te₅ with SiO₂ due to its higher activation energy and weaker thickness variation upon crystallization as well as its smaller crystal grain size in the crystalline state. Considering the adhesive strength with SiO₂, Si₂Sb₂Te₆ is a preferable candidate over Ge₂Sb₂Te₅ for future high density phase change random access memory application.