Thermal stability of dysprosium scandate thin films

The thermal stability of DyScO3 thin films in contact with SiO2 or HfO2 during annealing up to 1000°C has been studied. It is found that DyScO3∕SiO2 stacks react during annealing and a phase separation into polycrystalline Sc-rich (and relatively Si-poor) DySc silicate on top of an amorphous Dy-rich DySc silicate is observed. In contrast, DyScO3 is found to be thermodynamically stable in contact with HfO2 and to recrystallize upon annealing. These results demonstrate that the previously reported high crystallization temperature of >1000°C for DyScO3 is not an intrinsic material property but caused by silicate formation.