Mixed Al and Si doping in ferroelectric HfO2 thin films

Ferroelectric HfO2 thin films 10nm thick are simultaneously doped with Al and Si. The arrangement of the Al and Si dopant layers within the HfO2 greatly influences the resulting ferroelectric properties of the polycrystalline thin films. Optimizing the order of the Si and Al dopant layers led to a remanent polarization of similar to 20 mu C/cm(2) and a coercive field strength of similar to 1.2MV/cm. Post-metallization anneal temperatures from 700 degrees C to 900 degrees C were used to crystallize the Al and Si doped HfO2 thin films. Grazing incidence x-ray diffraction detected differences in peak broadening between the mixed Al and Si doped HfO2 thin films, indicating that strain may influence the formation of the ferroelectric phase with variations in the dopant layering. Endurance characteristics show that the mixed Al and Si doped HfO2 thin films exhibit a remanent polarization greater than 15 mu C/cm(2) up to 10(8) cycles. (C) 2015 AIP Publishing LLC.