Properties of transparent yttrium oxide dielectric films prepared by sol-gel process

In this research, yttrium oxide (Y ₂O ₃) gate dielectric films were deposited onto alkali-free glass substrates by a sol-gel process. This report describes the effects of annealing temperatures on the microstructural and electrical properties of sol-gel derived Y ₂O ₃ films. These sol-gel films were preheated at 300 °C for 10 min, and then annealed at 400-550 °C for 1 h. XRD results revealed that all annealed films exhibited preferential (2 2 2) orientation; films annealed at 450-550 °C were polycrystalline with cubic structures. The average transmittances of polycrystalline Y ₂O ₃ films were over 88.0% in the visible range. The electrical properties of the Y ₂O ₃ films were analyzed by capacitance-voltage (C-V) and current-voltage (I-V) measurements. Films annealed at 500 °C yielded the lowest leakage current density, 1.8 × 10 ^-7 A/cm ², at an applied voltage of 5 V, and had a dielectric constant of 10.0 at 100 kHz.