Dielectric property and conduction mechanism of ultrathin zirconium oxide films

Stoichiometric, uniform, amorphous ZrO2 films with an equivalent oxide thickness of similar to1.5 nm and a dielectric constant of similar to 18 were deposited by an atomic layer controlled deposition process on silicon for potential applications in metal-oxide-semiconductor (MOS) devices. The conduction mechanism is identified as Schottky emission at low electric fields and as Poole-Frenkel emission at high electric fields. The MOS devices showed low leakage current, small hysteresis (< 50 mV), and low interface state density (similar to 2x10(11) cm(-2) eV(-1)). Microdiffraction and high-resolution transmission electron microscopy showed a localized monoclinic phase of alpha -ZrO2 and an amorphous interfacial ZrSixOy layer which has a corresponding dielectric constant of 11. (C) 2001 American Institute of Physics.