The sputter deposition of highly ⟨100+001⟩‐textured tetragonal BaTiO3on unheated substrates using a pressed powder BaTiO3target and a radio frequency‐excited Ne discharge is reported. For comparison, amorphous BaTiO3was also produced, using an Ar discharge operated at the same value of all other independent process parameters.Insitudischarge diagnostics using optical emission spectrometry was used to study the plasma volume. Data show that there was atomic Ti but no atomic Ba in the Ne discharge used to producet‐BaTiO3. However, both atomic Ba and Ti were identified in the Ar discharge used to producea‐BaTiO3. A probable source of free Ba atoms in the plasma is the reduction of BaTiO3at the target surface due to the sputtering action of Ar+ions. By comparison with other sputter‐deposited metal oxide systems, the effect on film crystallinity of atomic metal versus molecular metal oxide flux incident on the substrate is discussed.