Effect of substrate type and temperature on the growth of thin Ru films by metal organic chemical vapor deposition

Ru thin films were deposited by pulsed metal organic chemical vapor deposition at 210 °C and 300 °C on SiO2 (native oxide)/(001)Si, HfSiON/SiON/(001)Si, and HfO2/SiON/(001)Si substrates from (2,4-dimethylpentadienyl)(ethylcyclopentadienyl)ruthenium [Ru(DMPD)(EtCp)]-O2. The effects of substrate and deposition temperature on the deposition of Ru thin films were investigated. The incubation time, the period in which film deposition was hardly observed at the early deposition stage, strongly depended on the substrate and the deposition temperature. In addition, incubation time and the deposition rate after the incubation time were almost independent of the Ru precursor concentration at 300 °C, suggesting that the deposition rate is limited by the surface reaction. Atomic force microscopy observations revealed that the average surface roughness, Ra, of the films deposited at 300 °C was lower than those deposited at 210 °C for all substrates. It was also clear that the Ra increased significantly with increasing incubation time. In addition, the film deposited at 300 °C showed lower resistivity than that deposited at 210 °C. These results clearly show that the Ru films deposited at 300 °C on SiO2 (native oxide)/(001)Si, HfSiON/SiON/(001)Si, and HfO2/SiON/(001)Si substrates show shorter incubation times with smoother surface and lower resistivity than those at 210 °C.