A novel evaluation method to determine the fractal dimension of SEM images: a study of Au/Pd/GaAs contacts during heat treatment

Heat treatment is an essential technological step for making ohmic contacts to compound semiconductors. During the heat treatment a remarkable volatile component (arsenic) loss takes place due to the thermal decomposition of GaAs and the interactions between Ga and the contact metals. Using a scanning electron microscope combined with a mass spectrometer it was possible to examine the changes of the surface pattern and to measure the As evaporation. We introduced a new method (soft segmentation) to determine the fractal dimension of multi-cluster images.