Thermal oxidation of silicon-on-insulator dots

We present a systematic study on the oxidation properties of Si dots on silicon-on-insulator material. Si dots with diameters varying from 60 down to 10 nm were realized and investigated in a transmission electron microscope. After thermal oxidation at 850 degrees C for different times the size and shape of the Si dots were analysed using energy-filtering transmission electron microscopy. The results show that the size of the dots is reduced with a reduced oxidation rate on smaller structures and indications for self-limiting effects. Further, the shape of the dots has changed significantly as the oxidation rate on curved surfaces is reduced with respect to planar surfaces. This effect therefore strongly depends on the aspect ratio of the structure.