Chemical vapor deposition of ultrathin Ta2O5 films using Ta[N(CH3)2]5

Abstract

Tantalum oxide films were deposited on Si substrates by chemical vapor deposition using the precursor $\mathrm{Ta}[{\mathrm{N(CH}}_{\mathrm{3}}{)}_2{]}_5,$ and an oxidizing agent—${\mathrm{O}}_{\mathrm{2}},$ ${\mathrm{H}}_{\mathrm{2}}\mathrm{O},$ or NO. Temperatures ranged between 400 and 500 °C and total pressures between ${10}^{\text{−3}}$ and 9 Torr. NO did not lead to satisfactory film growth rates. Insignificant $\text{(<1\hspace{0.17em}}\mathrm{at.}\mathrm{\hspace{0.17em}\%)}$ N and up to a few percent C are incorporated when ${\mathrm{O}}_{\mathrm{2}}$ is the oxidant and the total pressure is in the Torr regime. In the milliTorr regime, the ${\mathrm{Ta}}_{\mathrm{2}}{\mathrm{O}}_{\mathrm{5}}$ films, grown using either ${\mathrm{O}}_{\mathrm{2}}$ or ${\mathrm{H}}_{\mathrm{2}}\mathrm{O},$ contain readily detectable amounts of C and N. For the films grown with ${\mathrm{O}}_{\mathrm{2}}$ in the Torr regime, leakage currents were significantly lowered when the flow rate of ${\mathrm{O}}_{\mathrm{2}}$ increased from 100 to 900 sccm.