Pulsed-Chemical vapor deposition of Ruthenium and Ruthenium dioxide thin films Using RuO_4 precursor for the DRAM capacitor electrode

摘要

Ru and RuO_2 thin films were grown on Si, SiO_2 and TiN substrates by pulsed chemical vapor deposition using RuO_4 and 5%H_2/95%N_2 as the precursor and reducing gas, respectively. Ru film showed an excellent thermal stability, high growth rate of 0.18nm/pulse (0.43nm/min), low impurity concentration, conformal step coverage and very smooth surface. The TiO_2 film grown on this Ru electrode showed much improved electrical performance compared to those on the other Ru electrode. RuO_2 thin film can be deposited by decreasing the H_2/N_2 gas supply rate. RUO_2 thin film has excellent conformal step coverage on a hole structure with an opening diameter of 100nm and a depth of 1000nm. With RuO_2 thin film as sub-electrode of MIM capacitor, the equivalent oxide thickness of TiO_2 film could be decreased to 0.56nm within the specification of DRAM leakage current.