Improvement in the leakage current characteristic of metal-insulator-metal capacitor by adopting RuO_2 film as bottom electrode

摘要

The dielectric constant, equivalent oxide thickness (t_(ox)), and leakage current properties of Pt/(Al-doped)TiO_2/RuO_2 capacitors were examined in comparison with Pt/(Al-doped)TiO_2/Ru capacitors. The Al-doped TiO_2 and undoped TiO_2 films grown on RuO_2 showed high dielectric constants of 60 and 102, respectively. The minimum t_(ox) of these films were 0.46 nm and 0.56 nm, respectively, while still satisfying the dynamic random access memory leakage current density specification (< 1 x 10~(-7) Acm~(-2) at capacitor voltage of 0.8 V). These excellent electrical properties of (Al-doped) TiO_2 on RuO_2 were attributed to the high work function and the reduced interfacial effect on RuO_2.