Hafnium oxide gate dielectric for strained-Si_1-xGe_x

Ultrathin hafnium oxide (HfO₂) films have been deposited by rf sputtering on strained-Si_0.81Ge_0.19 films. The structure and chemical composition of the deposited films have been studied using high resolution transmission electron microscopy, time-of-flight secondary ion mass spectroscopy and X-ray photo-electron spectroscopy techniques. Current conduction mechanism in HfO₂ films has been studied using current-voltage (I-V) characteristics. The leakage current is found to be dominated by the Schottky emission at a low electric field, whereas Poole-Frenkel emission takes over at a high electric field.