A first-principles study of Cu and Al doping in ZrO₂ for RRAM device applications

First-principle calculations were carried out to calculate formation energy, charge density and electronic properties of doped ZrO₂ with and without single oxygen vacancy (V_o) using density functional theory (DFT). Increasing concentration of Al dopant without V_o decreased the conductivity of the system (ZrO₂) and vice versa in case of Cu dopant. Isosurface charge density plots confirmed that conducting channels were created in both cases in addition to that Al dopant with V_o improved the conductivity and enhanced conducting channel. The ZrO₂ doped with Cu formed conducting channel (metal ions) and enhanced the conductivity, while Cu with V_o was less conductive with shortened conducting channels. These results showed impacts of dopants (metal ions) with and without oxygen vacancy to increase the efficiency of non-volatile RRAM devices. Electronic properties confirmed that ZrO₂ with substitutional doping of Al having V_o was comparatively better electrode material for RRAM technology while Cu without Vo. These studies showed that ZrO2 based RRAM devices have an excessive potential for future memory applications.