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

In this research, yttrium oxide (Y2O3) 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 Y2O3 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 Y2O3 films were over 88.0% in the visible range. The electrical properties of the Y2O3 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/cm2, at an applied voltage of 5 V, and had a dielectric constant of 10.0 at 100 kHz.