Growth of Ru/RuO2 layers with atomic vapor deposition on plain wafers and into trench structures

Using beta-diketonate Ru precursors diluted in n-octane Ru and RuO2 layers were grown on plane 200 nm SiO2/Si wafers by atomic vapor deposition (AVD®). AVD® was carried out in an AIXTRON Tricent® system using liquid delivery of the ruthenium precursor. The deposited multi-crystalline smooth (RMS surface roughness <1 nm) Ru layers are preferable orientated along the (002) plane and exhibit a near bulk sheet resistivity of around 10 μΩ cm for 20 nm films with a uniformity better than 1.5%. By adding oxygen during the AVD® process homogenous multi-crystalline RuO2 films are processed with a sheet resistivity of about 80 μΩ cm (for 30 nm layer thickness) and uniformity better than 2%. Growth of Ru into trench structures is achieved by working with a pure Ru precursor in its kinetic growth regime. Highly conformal Ru thin films were deposited at 300 °C–320 °C on trench structures. Depending on the deposition parameters like reactor pressure, injection frequency and opening time good Ru step coverage in trenches is achieved. More than 90% step coverage is obtained for structures with aspect ratios of 1:10.