The Property of Ta2O5 on Chemical Vapor Deposited Ru Film Fabricated using Tris(2,4-octanedionato)ruthenium for Application to Dynamic Random Access Memory Capacitor

Chemical vapor deposited (CVD) Ru was adopted as a bottom electrode of Ta2O5 capacitor for application to gigabit scale dynamic random access memory (DRAM). Ru film was deposited with the precursor of tris(2,4-octanedionato)ruthenium, Ru(od)3, at 260°C in O2 ambient. We obtained Ru film with 44 µΩ·cm of electric resistivity after annealing at 700°C. The root mean square (RMS) surface roughness of the film was 3.3 nm on SiO2 and 7.4 nm on TiN. We also obtained a leakage current of 4.45×10-9 A/cm2 at 1 V with a SiO2 equivalent thickness of 1.12 nm in the TiN/Ta2O5/Ru capacitor. Double plasma treatment on Ta2O5 was more effective than single plasma treatment for obtaining low leakage current. The TiN layer under Ru was oxidized into TiO x during the rapid thermal process (RTP) annealing of the Ru film at 600°C in N2 ambient. The remaining oxygen in the Ru film is believed to be an oxygen source for the oxidation of TiN.