Electrical characteristics of $Ga2O3–TiO2$ nanomixed films grown by plasma-enhanced atomic-layer deposition for gate dielectric applications

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 $∼6Å$ 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 $∼4×10−3A∕cm2$ at $−1.5V$ and an interfacial charge density of $1.5×1011cm−2eV−1$⁠. The $Ga2O3–TiO2$ nanomixed films are new candidate materials for gate dielectric applications.