Structural and Electrical Properties of Lanthanum Gadolinium Oxide: Ceramic and Thin Films for High-k Application

LaGdO3 (LGO) ceramics and thin films were prepared for high-k applications. Electrical properties of LGO ceramics were studied as a function of temperature and frequency using metal-insulator-metal (MIM) capacitor configuration. The dielectric constant and loss tangent at 100 kHz were 20 and 0.004 respectively at ambient conditions without any temperature and voltage dependence. Bulk properties are encouraging for high-k gate-oxide applications. Thin films of LGO were prepared on Si substrates by pulsed laser deposition. The electrical properties of thin films were investigated with metal-insulator-semiconductor (MIS) capacitors. The relative dielectric permittivity was 21.6 +/- 1.7 and the equivalent oxide thickness was controlled by the SiOx interlayer. However, compared to the standard SiO2 capacitors of similar equivalent oxide thickness, less leakage currents were obtained. By controlling the interlayer growth between the high-k and silicon, EOT can be reduced further to meet the requirements of 22 nm technology node with lower leakage current utilizing this material