Electrical properties of ZrO₂ gate dielectric on SiGe

We report the electrical properties of a high dielectric constant (high-k) material, ZrO₂, deposited directly on SiGe, without the use of a Si buffer layer or a passivation barrier. ZrO₂ thin films of equivalent oxide thickness (EOT) down to 16.5 Å were deposited on strained SiGe layers by reactive sputtering. Results indicate that ZrO₂ films on SiGe have good interfacial properties and low leakage currents. Sintering in forming gas at 350 °C for 1 h could further improve the film quality. Although threshold voltage stability and dielectric dispersion become a concern for thick ZrO₂ films, thin ZrO₂ films of EOT less than 20 Å exhibit excellent electrical properties making them a good candidate for SiGe applications. © 2000 American Institute of Physics.