PLD of perovskite coatings for optoelectronics, microelectronics, and microtechnology

The deposition of BaTiO3 thin films by pulsed excimer laser radiation (248 nm) on Pt/Ti/Si(111) and Pt/Ti/Si(100) substrates is investigated as a function of the processing variables laser fluence, processing gas pressure and target-to-substrate distance. The influence of the kinetic energy of the film-forming particles on the crystalline structure, defects and orientation and on the resulting electrical properties of the films is investigated. X-ray diffraction measurements and polarisation-dependent micro Raman measurements reveal a c-axis orientation normal to the substrate surface, in the case of high particle energy (> 50 eV), while at low kinetic energies (<30 eV) a [111]pc or [110]pc orientation is preferred. The ferroelectricity and the dielectric constant of the films, determined by impedance measurements, decrease with increasing kinetic energy of the film-forming particles from εr=1000–2200 to εr=200–700. This decrease correlates with the change of the orientation and with an increasing lattice constant of the films, indicating that particles with high kinetic energies produce crystal defects and stress in the growing film.