This is a copy of the slides presented at the meeting but not formally written up for the volume.

Pulsed Laser Deposition (PLD) has become a widespread technique for fabrication of thin films. A powerful pulsed laser is used to create a plasma off a target material, which is subsequently epitaxially deposited on a heated single crystal substrate. The PLD process can take place at relatively high oxygen pressures (up to 100 Pa), thereby making it especially suited for the deposition of complex oxides. For the purpose of studying the crystalline structure of the film during growth, a special sample chamber has been constructed to be used with synchrotron X-rays. The first results of deposition of thin films of YBa2Cu3O7-ä as well PbTiO3 on SrTiO3 substrates were obtained at the European Synchrotron Radiation Facility. From intensity oscillations of the specularly reflected X-ray beam it is concluded that growth proceeds in a layer-by-layer fashion. Deposition was interrupted several times, which allowed for detailed structural characterization of the grown film at the deposition temperature of 780°C, where pronounced Kiessig fringes show that the surface is particularly smooth. A simple growth model, which contains a large degree of inter-layer mass transport, is used to describe the data and shows that a quantitative interpretation of the data is possible.