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 Angstrom 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 degrees 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 Angstrom exhibit excellent electrical properties making them a good candidate for SiGe applications. (C) 2000 American Institute of Physics. [S0003-6951(00)01002-0].