Improved thin film growth using Slow Kinetics Intermittent Sputtering

Radio-frequency off-axis magnetron sputtering is a well established technique to produce high quality epitaxial thin films of complex oxides. It has been successfully used for over two decades to grow thin films, superlattices and even solid solutions. The main drawback is the common lack of in situ monitoring of the growth, which can significantly slow down the optimisation of the many growth parameters. However, once the optimal parameters are found, they are usually very stable in time, leading to consistently high quality thin films. One of the main growth parameters is the growth temperature, with typical optimal ranges as narrow as 20 °C. Here, using the prototypical ferroelectric PbTiO$_3$ as a model system, we show that by periodically interrupting the deposition process to allow the deposited material to relax, we can significantly increase the temperature range over which we obtain atomically flat surfaces to more than 50 °C. Moreover, the overall crystalline quality is greatly improved, as shown by X-ray diffraction. Finally, we demonstrate the applicability of this method to other materials.