Influences of different oxidants on the characteristics of HfAlO_x films deposited by atomic layer deposition

A comparative study of two kinds of oxidants (H₂O and O₃) with the combinations of two metal precursors trimethylaluminum (TMA) and tetrakis(ethylmethylamino) hafnium (TEMAH) for atomic layer deposition (ALD) hafnium aluminum oxide (HfAlO_x) films is carried out. The effects of different oxidants on the physical properties and electrical characteristics of HfAlO_x films are studied. The preliminary testing results indicate that the impurity level of HfAlO_x films grown with both H₂O and O₃ used as oxidants can be well controlled, which has significant effects on the dielectric constant, valence band, electrical properties, and stability of HfAlO_x film. Additional thermal annealing effects on the properties of HfAlO_x films grown with different oxidants are also investigated.