Chemically conformal deposition of SrTiO_3 thin films by Atomic Layer Deposition using conventional metal organic precursors and remote-plasma activated H_2O

摘要

Chemically conformal deposition of SrTiO_3 (STO) thin films was successfully achieved by ALD using conventional metal organic precursors and remote-plasma activated H_2O. It was found that the ALD behavior of the STO film was critically dependent on the Sr(thd)_2 source bubbling temperature. When the Sr-source bubbling temperature was < ～ 200℃ (Sr(thd)_2 melting temperature), the deposition proceeded in a genuine ALD mode and stoichiometric STO films were deposited with a good process reliability. Relatively good electrical properties were obtained from a planar capacitor structure with Pt top and Ru bottom electrodes. A 19.5-nm-thick STO film showed an equivalent oxide thickness (EOT) of 0.8 nm and a leakage current density of 1.98 x 10~(-6) A/cm~2 at 1V after post-annealing.