A method for forming a Ti-containing film on a substrate by plasma-enhanced atomic layer deposition (PEALD) using tetrakis(dimethylamino)titanium (TDMAT) or tetrakis(diethylamino)titanium (TDEAT), includes: introducing TDMAT and/or TDEAT in a pulse to a reaction space where a substrate is placed; continuously introducing a NH3-free reactant gas to the reaction space; applying RF power in a pulse to the reaction space wherein the pulse of TDMAT and/or TDEAT and the pulse of RF power do not overlap; and repeating the above steps to deposit a Ti-containing film on the substrate.