Praseodymium silicate as a high-k dielectric candidate:: An insight into the Pr2O3-film/Si-substrate interface fabricated through a metal-organic chemical vapor deposition process

Praseodymium-containing thin films have been deposited on Si(001) substrates by metal-organic chemical vapor deposition (MOCVD) from the Pr(tmhd)(3) (H-tmhd = 2,2,6,6-tetramethyl-3,5-heptanedione) precursor. The structural, compositional, and morphological film characterization has been investigated using X-ray diffraction (XRD), angle-resolved X-ray photoelectron spectroscopy (AR-XPS), and transmission electron microscopy (TEM). Detailed studies of the deposition parameters indicate that the MOCVD process is governed by a kinetic regime and that some reactive phenomena occur at the film/substrate interface, forming a praseodymium silicate layer. A possible explanation for interfacial interaction has been proposed, taking into account the diffusion of Si from the substrate towards the bulk and that of oxygen from the film surface toward the substrate/ film interface. Finally, the electrical characterization of the praseodymium silicate layer has been carried out in order to evaluate its potential implementation as an alternative dielectric. Its dielectric constant has been evaluated to be similar to 8.