Electrical properties and conduction mechanisms in HfxTiySizO films obtained from novel MOCVD precursors

We have investigated electrical behaviour of high-k Hf_xTi_ySi_zO layers with different Hf:Ti ratios in the film. The films are prepared by MOCVD using novel single-source precursors. Oxide and interface charges, leakage currents and conduction mechanisms are found to be a strong function of the film composition. The films with lower Hf content show lower level of oxide and interface charges and higher dielectric constant whereas those with higher Hf content have better leakage current properties. It is established that in the films with lower Hf content the conduction is governed by a phonon-assisted process, i.e. it is defined rather by the intrinsic properties of the layer than by its defect structure.