Physical properties of Y ₂O ₃ films fabricated by the reactive ionized cluster beam deposition technique

Heteroepitaxial Y ₂O ₃ films on Si(100) were grown by the ionized cluster beam (ICB) deposition technique. The composition of the deposited film was investigated using Rutherford backscattering spectroscopy. The composition ratios of the Y ₂O ₃ films changed with changes in the deposition conditions. In the case of the film which was fabricated under optimum conditions, the ratio of Y to O was 1 to 1.55. The crystal orientational relation of the films deposited on a Si (100) substrate was investigated by using reflection high-energy electron diffraction. We found that the orientation of the deposited film changed mainly due to changes of the substrate temperature and the cluster acceleration energy. Y ₂O ₃ films were epitaxially grown above 800°C without acceleration, and heteroepitaxial growth of Y ₂O ₃ films on Si(100) substrates was possible with a 5-kV acceleration voltage above 650°C. The epitaxial relationship between Y ₂O ₃ and Si(100) was Y ₂O ₃(110)//Si(100) and Y ₂O ₃[110]//Si[100] or Y ₂O ₃(110)//Si(100) and Y ₂O ₃[100]//Si[100]. The I-V characteristics of Al/Y ₂O ₃/Si metal-insulator-semiconductor devices were investigated. After thermal annealing in an oxygen ambient, the measured value of the breakdown strength was more than 3 MV/cm and the leakage current was lower than 1 × 10 ^-10 A/cm ².