Effect of Y2O3 interlayer on the electric properties of Y-doped HfO2 film deposited by chemical solution deposition

Ferroelectric oxide becomes the focus of memory industry again after the discovery of ferroelectricity in doped-HfO2 polycrystalline films. Thermal stress is an important factor for the variation of ferroelectric phase content. In this paper, the effect of film stress induced by Y2O3 interlayer in the ferroelectric properties of Y-doped HfO2 (Y: HfO2) ferroelectric films, which is deposited by chemical solution deposition (CSD), is investigated system-atically by polarization-voltage measurement. Compared with Y-doped HfO2 film without interlayer, 1 nm Y2O3 interlayer enhances the remanent polarization of Y: HfO2 film due to the effects of film stress and surface energy. And thick Y2O3 interlayer benefits to reduce leakage current density. But polarization switching of HfO2 film is restrained due to the capacitor voltage divider caused by thick Y2O3 interlayer. The obvious enhance effect of Y2O3 interlayer still exists in Y: HfO2 film at high voltage due to the breakdown of Y2O3 interlayer, realizing a huge remanent polarization (Pr) of 22.8 mu C/cm2 in Y: HfO2 film (doping content: 4 at %). It is 3.6 times than that of ferroelectric doped-HfO2 film without Y2O3 interlayer.

Automated summary

This paper systematically investigates the effect of film stress induced by Y2O3 interlayer on the ferroelectric properties of Y-doped HfO2 films deposited by chemical solution deposition. The results show that a 1 nm Y2O3 interlayer enhances the remanent polarization of Y-doped HfO2 films and reduces leakage current density. However, a thick Y2O3 interlayer restricts the polarization switching of HfO2 films due to the capacitor voltage divider effect. At high voltage, the rupture of the Y2O3 interlayer enhances the remanent polarization of Y-doped HfO2 films, achieving a large remanent polarization of 22.8 μC/cm2, which is 3.6 times higher than that of undoped HfO2 films without Y2O3 interlayer.