Chemical solution deposition of ferroelectric Sr:HfO2 film from inorganic salt precursors

Abstract

Strontium doped hafnium oxide (Sr:HfO2) ferroelectric thin films with strontium concentrations ranging from 0 to 20mol% were processed with inorganic hafnium source and strontium source using a chemical solution deposition technique. The co-existence of monoclinic phase and ferroelectric orthorhombic phase in the Sr doped HfO2 thin film was confirmed by x-ray diffraction and high-resolution transmission electron microscopy results. The atomic force microscope measurements were adopted and the thin films showed crack-free surface. The intrinsic ferroelectricity of the doped HfO2 thin films could be demonstrated by polarization–voltage hysteresis loops together with piezoelectric force microscope. The maximum twofold remnant polarization value of 3.02 μC/cm2 with a coercive field of 2.0 MV/cm was achieved when the Sr content was 7.5 mol%. Meanwhile, the polarization didn't show obvious degradation until 107 electric cycles, indicating the good fatigue performance of the Sr:HfO2 film. These findings indicate that it is a feasible way to prepare Sr:HfO2 ferroelectric thin films via chemical solution deposition with inorganic salt precursors.