Thin BaHfO3 high-k dielectric layers on TiN for memory capacitor applications

Abstract

Thin BaHfO3 dielectric films were investigated in view of future dynamic random access memory applications. The dielectric layers were prepared by physical vapor codeposition of BaO and HfO2 onto metallic TiN substrates. Films deposited at 400°C are amorphous, show low leakage [J(1V)<10−8A∕cm2] at capacitance equivalent thicknesses (CETs) down to ∼2nm and a dielectric constant of ∼23. Rapid thermal annealing of the amorphous BaHfO3 films induces crystallization in the cubic perovskite phase with a dielectric constant of ∼38. This k value was observed for films as thin as 8nm enabling CET value of ∼0.9nm.