Enhancing the ferroelectricity and durability in Sm doped HfO2 thin films prepared by CSD method

In this study, Sm-doped HfO2 (Hf1-xSmxO2) thin films on Pt/TiN/SiO2/Si substrates were fabricated using chemical solution deposition (CSD) method. The effects of Sm doping concentration on the microstructure and ferroelectric properties of Hf1-xSmxO2 films were systematically investigated. Grazing-incidence X-ray diffraction (GIXRD) analysis and ferroelectric property measurements of the polycrystalline Sm:HfO2 films with thicknesses ranging from 60 to 88 nm, revealed that samples doped with 2.50% Sm exhibited optimal ferroelectric characteristics with a residual polarization (Pr) of 15.96 µC/cm2 and a coercive field (Ec) of 1.03 MV/cm after annealing at 800℃. Interestingly, the 2.50% Sm-doped sample also demonstrates excellent endurance and retention properties, sustaining over 108 switching cycles without breakdown. Furthermore,  density functional theory (DFT) calculations were conducted to elucidate the regulation mechanism of doping samarium on the ferroelectric properties of HfO2 films. The well consistency of the computational results and experimental observations, indicating that samarium doping is a feasible strategy for enhancing the ferroelectric properties of hafnium oxide films.