Published online by Cambridge University Press: 28 August 2019
Using ab initio simulation, we study a ferroelectric layer of a few nanometers made of hafnia (HfO2) under the influence of Si doping with TiN electrodes. We evaluate the orthorhombic phase of Pca21 symmetry, its ferroelectric switching and the incidence of doping with silicon. We show that the ferroelectric switching can involve a 90° characteristic angle with corresponding activation energy which is lowered by a factor three due to Si doping at 3% at. A full MFM (Metal-Ferroelectric-Metal) model is derived in order to simulate finite-size effects. This model is compatible with a reversal of a polar HfO2:Si with a (111) preferential orientation. Validity and usefulness of such a model are discussed for ferroelectric devices optimization.