Growth kinetics of chemical-vapor-deposited Pb(Zrx,Ti1-x)O3 films from a Pb(C2H5)4/Zr(O-t-C4H9)4/Ti(O-i-C3H7)4/O2 reaction system

Lead zirconate titanate (PZT) films were deposited on Pt-coated Si substrates by means of the low-pressure chemical vapor deposition (LPCVD) technique using tetraethyl lead (Pb(C2H5)(4)), zirconium tert-butoxide (Zr(O-t-C4H9)(4)), titanium tetra isopropoxide (Ti(O-i-C3H7)(4)), and oxygen (O-2) as reactants at temperatures ranging from 773 to 853K. The film growth kinetics was studied by investigating the growth rate dependencies at various substrate temperatures and reactant concentrations of Pb(C2H5)(4), Zr(O-t-C4H9)(4), Ti(O-i-C3H7)(4), and O-2, respectively. The film growth rate obeyed Langmuir-Hinshelwood typed kinetics with respect to Pb(C2H5)(4) and O-2 but increased linearly with the concentrations of the B-site precursors, i.e., Zr(O-i-C4H9)(4) and Ti(O-i-C3H7)(4). An Eley-Rideal mechanism that considers a surface reaction among two adsorbed species, Pb(C2H5)(4) and O-2, and two gaseous species, Zr(O-t-C4H9)(4) and Ti(O-i-C3H7)(4), was established to describe the PZT film growth behavior. Growth rate fitting with respect to the reaction temperature gave an adsorption energy of about -51.5 kcal/mol, indicating strong surface adsorption characteristic of Pb(C2H5)(4) during the film growth process.