Improved sputter depth resolution in Auger composition-depth profiling of polycrystalline thin film systems using single grain depth profiling

Today in-depth profiling of microelectronics thin film systems is one of the important applications of Auger electron spectroscopy. It is used to monitor the elemental in-depth composition after different manufacturing processes to control the quality of these processes. For instance, the layer interdiffusion and reactions with various process gases are analyzed. In addition, interface contaminations have to be controlled, because they strongly influence the properties of the whole thin film system. For polycrystalline layers, the depth resolution of sputter depth profiling is limited by the sputter yield differences attributed to grains having different crystalline orientations relative to the incoming ion beam. If depth profiling can be performed on single grains only, the poor depth resolution caused by these sputter yield differences can be avoided. Unfortunately, the approach works only on a few samples because single grains must be identified and have to have grain sizes that are in the dimensions of the layer thickness. Using methods of in situ sample preparation, however, allows application of single grain depth profiling to an extended range of thin film systems. Copyright (C) 2006 John Wiley & Sons, Ltd.