Sputter deposition of highly 〈100+001〉-textured tetragonal barium titanate on unheated silica using a neon discharge

Abstract

The sputter deposition of highly 〈100+001〉-textured tetragonal BaTiO3 on unheated substrates using a pressed powder BaTiO3 target and a radio frequency-excited Ne discharge is reported. For comparison, amorphous BaTiO3 was also produced, using an Ar discharge operated at the same value of all other independent process parameters. In situ discharge 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 produce t-BaTiO3. However, both atomic Ba and Ti were identified in the Ar discharge used to produce a-BaTiO3. A probable source of free Ba atoms in the plasma is the reduction of BaTiO3 at 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.