Nanomixed Ga2O3–TiO2 films with 5 nm thickness were deposited at 200 °C on Si (001) substrates using plasma-enhanced atomic-layer deposition for gate dielectric applications. While TiO2 films deposited on Si substrates are crystallized at an annealing temperature of 500 °C, Ga2O3–TiO2 nanomixed films show an incipient crystallization at 950 °C and exhibited a good thermal stability even at about 950 °C for 1 min. The dielectric constant of TaN/Ga2O3–TiO2/Si capacitors is larger than that of TaN/TiO2–Ga2O3/Si capacitors in nanomixed films annealed at 900 °C for 1 min. The EOT of the TaN/Ga2O3–TiO2/Si capacitors was ∼6 Å up to an annealing temperature of 700 °C but increases with increasing annealing temperature above 700 °C for 1 min. The TaN/Ga2O3–TiO2/Si capacitors annealed at 1000 °C exhibit a leakage current density of ∼4×10-3 A/cm2 at -1.5 V and an interfacial charge density of 1.5×1011 cm-2 eV-1. The Ga2O3–TiO2 nanomixed films are new candidate materials for gate dielectric applications.