Growth, microstructure, and resistivity of RuO₂ thin films grown by metal-organic chemical vapor deposition

Polycrystalline RuO₂ thin films were grown by metal-organic chemical vapor deposition (MOCVD) on both SiO₂/Si(001) and Pt/Ti/SiO₂/Si(001) substrates. Films having a controllable and reproducible structural texture and phase purity were synthesized by carefully controlling deposition parameters. Moderate growth temperatures (∼350 °C) and low growth rates (<30 Å/min) produced highly (110)-textured RuO₂ films. Highly (101)-textured RuO₂ films were favored at slightly lower temperatures (∼300 °C) and much higher growth rates (>30 Å/min). The most conductive RuO₃ films had resistivities of 34 to 40 µΩ−cm at 25 °C, an average grain size of 65 ± 15 nm, and a surface roughness (rms) of 3 to 10 nm. Both single-phase Ru and mixed Ru/RuO₂ phase material were also fabricated at low temperatures (<350 °C) by using lower oxygen flow concentrations (<10%).