Thickness dependence of dielectric properties in sub-nanometric Al2O3/ZnO laminates

International audienceIn recent years, laminates consisting of alternating layers of two binary oxides with layer thicknesses below 1 nm have attracted attention for their high dielectric constant values, reaching values of about 1000 in the case of Al2O3/TiO2 sub-nanometric laminates. This excellent dielectric performance of the sub-nanometric laminates relies on the Maxwell Wagner (MW) relaxation, exploiting the blocking of the mobile charge carriers of the semiconducting TiO2 at the interface with Al2O3. In this work, we explore the possibilities of enhancing the dielectric constant by MW relaxation in amorphous sub-nanometric laminates of Al2O3/ZnO. We demonstrate that the sublayer thickness and the interface of individual layers define the apparent dielectric constant of the laminates. In addition or further understanding, simulations and equivalent circuit analysis of the sub-nanometric laminates were conducted

Thickness dependence of dielectric properties in sub-nanometric Al2O3/ZnO laminates

International audienceIn recent years, laminates consisting of alternating layers of two binary oxides with layer thicknesses below 1 nm have attracted attention for their high dielectric constant values, reaching values of about 1000 in the case of Al2O3/TiO2 sub-nanometric laminates. This excellent dielectric performance of the sub-nanometric laminates relies on the Maxwell Wagner (MW) relaxation, exploiting the blocking of the mobile charge carriers of the semiconducting TiO2 at the interface with Al2O3. In this work, we explore the possibilities of enhancing the dielectric constant by MW relaxation in amorphous sub-nanometric laminates of Al2O3/ZnO. We demonstrate that the sublayer thickness and the interface of individual layers define the apparent dielectric constant of the laminates. In addition or further understanding, simulations and equivalent circuit analysis of the sub-nanometric laminates were conducted

Thickness dependence of dielectric properties in sub-nanometric Al2O3/ZnO laminates

International audienceIn recent years, laminates consisting of alternating layers of two binary oxides with layer thicknesses below 1 nm have attracted attention for their high dielectric constant values, reaching values of about 1000 in the case of Al2O3/TiO2 sub-nanometric laminates. This excellent dielectric performance of the sub-nanometric laminates relies on the Maxwell Wagner (MW) relaxation, exploiting the blocking of the mobile charge carriers of the semiconducting TiO2 at the interface with Al2O3. In this work, we explore the possibilities of enhancing the dielectric constant by MW relaxation in amorphous sub-nanometric laminates of Al2O3/ZnO. We demonstrate that the sublayer thickness and the interface of individual layers define the apparent dielectric constant of the laminates. In addition or further understanding, simulations and equivalent circuit analysis of the sub-nanometric laminates were conducted

Study on the dielectric properties of Al2O3/TiO2 sub-nanometric laminates effect of the bottom electrode and the total thickness

International audienceDielectrics based on amorphous sub-nanometric laminates of TiO2 and Al2O3 are subject to elevated dielectric losses and leakage currents, in large parts due to the extremely thin individual layer thickness chosen for the creation of the Maxwell-Wagner relaxation and therefore the high apparent dielectric constants. The optimization of performances of the laminate itself being strongly limited by this contradiction concerning its internal structure, we will show in this study that modifications of the dielectric stack of capacitors based on these sub-nanometric laminates can positively influence the dielectric losses and the leakage, as for example the nature of the electrodes, the introduction of thick insulating layers at the laminate/electrode interfaces and the modification of the total laminate thickness. The optimization of the dielectric stack leads to the demonstration of a capacitor with an apparent dielectric constant of 90, combined with low dielectric loss (tan delta) of 7 . 10(-2) and with leakage currents smaller than 1 x 10(-6) A cm(-2) at 10 MV m(-1)

Study on the dielectric properties of Al2O3/TiO2 sub-nanometric laminates effect of the bottom electrode and the total thickness

Dielectrics based on amorphous sub-nanometric laminates of TiO2 and Al2O3 are subject to elevated dielectric losses and leakage currents, in large parts due to the extremely thin individual layer thickness chosen for the creation of the Maxwell-Wagner relaxation and therefore the high apparent dielectric constants. The optimization of performances of the laminate itself being strongly limited by this contradiction concerning its internal structure, we will show in this study that modifications of the dielectric stack of capacitors based on these sub-nanometric laminates can positively influence the dielectric losses and the leakage, as for example the nature of the electrodes, the introduction of thick insulating layers at the laminate/electrode interfaces and the modification of the total laminate thickness. The optimization of the dielectric stack leads to the demonstration of a capacitor with an apparent dielectric constant of 90, combined with low dielectric loss (tan delta) of 7 . 10(-2) and with leakage currents smaller than 1 x 10(-6) A cm(-2) at 10 MV m(-1)

Structural and Dielectric Properties of Subnanometric Laminates of Binary Oxides

Capacitors with a dielectric material consisting of amorphous laminates of Al2O3 and TiO2 with subnanometer individual layer thicknesses can show strongly enhanced capacitance densities compared to the bulk or laminates with nanometer layer thickness. In this study, the structural and dielectric properties of such subnanometer laminates grown on silicon by state-of-the-art atomic layer deposition are investigated with varying electrode materials. The laminates show a dielectric constant reaching 95 combined with a dielectric loss (tan δ) of about 0.2. The differences of the observed dielectric properties in capacitors with varying electrodes indicate that chemical effects at the interface with the TiN electrode play a major role, while the influence of the local roughness of the individual layers is rather limited