Growth Characteristics and Film Properties of Cerium Dioxide Prepared by Plasma-Enhanced Atomic Layer Deposition

CeO2 thin films were deposited by plasma-enhanced atomic layer deposition (PE-ALD). Novel Ce(iPrCp)3 [tris(isopropyl-cyclopentadienyl)cerium] was used as a Ce precursor, which showed clean evaporation with no residue and good thermal stability. For PE-ALD, O2 plasma was used as an oxidizing reactant. The PE-ALD process exhibited ALD mode with good self-saturation behavior and linear growth without any nucleation delay on Si substrate as a function of growth cycles. Additionally, it produced highly pure and nearly stoichiometric CeO2 films with polycrystalline cubic phases. Electrical properties of Al/CeO2/p-Si capacitors were improved by O2 annealing with reduction in interface state density (Dit), hysteresis, effective oxide charge (Qeff) and leakage current density. These experimental results indicate that the PE-ALD CeO2 using Ce(iPrCp)3 precursor can be viable option as a future high-k material in the microelectronic industry.