Growth of ceramic thin films by pulsed laser deposition. The role of the kinetic energy of laser ablated particles

Sintered targets of ZrO2, Al2O3 and BaTiO3 are ablated by KrF excimer laser radiation lambda=248 mn,tau=25 ns. The processing gas atmosphere consists Of O2 at typical pressures of 10(exp -3)-0.5 mbar. The films are deposited on a Pt/Ti/Si multilayer substrate.The investigations concentrate on the influence of the kinetic energy of the ablated particles on the crystal structure and morphology of the forming films. The kinetic energy is described as a function of the processing gas pressure, the target-to-substrate distance and the fluence of the laser radiation on the target. The compaction of the zirconia and alumina thin films is achieved by particles impinging on the growing surface with kinetic energies above 30 eV. To deposit ferroelectric BaTiO3 thin films at low substrate temperatures the mean kinetic energy of the Ba particles have to be < 30 eV to prevent displacements beneath the film surface. Analytical techniques used for the structural characterisation of the films are X-ra y diffraction , micro-Raman spectroscopy and electron microscopy. Dielectric and ferroelectric properties of the films are determined by impedance measurements. The thickness and the complex refractive index are determined by fitting a model for the film geometry to the measured ellipsometry data.