Direct liquid injection metal organic chemical vapor deposition of Nd 2O 3 thin films using Tris(2,2,6,6-tetramethyl-3,5-heptanedionato) neodymium

Abstract

Thin oxide films of Nd 2O 3 were prepared, using direct liquid injection metal organic chemical vapor deposition technique with Tris(2,2,6,6-tetramethyl-3,5-heptanedionato) neodymium dissolved in tetrahydrofuran, for gate dielectric oxides. We confirmed that the optimum vaporizer temperature was 220 °C and the apparent activation energy for the deposition was 12.2 kJ/mol. Above 550 °C, it appeared that the precursor was dissociated in the gas phase and the deposition rate was decreased. Nd 2O 3 film deposited at 475 °C has cubic phase structure with smooth morphology. When annealing temperature was raised to 800 °C, the crystallinity and grain size were increased and the property of the Nd 2O 3 films was improved. At an annealing temperature of 1000 °C, phase transition was observed with increase in leakage current and roughness of the film. The effective k value and the leakage current of the Nd 2O 3 film deposited at 475 °C was 15.3 and 2.8 × 10 − 4 A/cm 2 at 5 V, respectively. Nd oxide seems to be one of the most promising candidates as a gate dielectric oxide with high dielectric constant and low leakage current.