Salvo Mirabella

Self-interstitial Diffusion and Clustering in Crystalline Si: Experimental Analysis of the Interactions Between the Point Defect and Carbon or Boron Atoms Salvo Mirabella

This thesis is aimed to contribute to the present physical knowledge on native point defects in Si with our investigation on the diffusive properties of self-interstitials in crystalline silicon and on their interactions with some impurity species, such as carbon and boron atoms. Self-interstitials detection is a quite difficult task, still they are involved in many phenomena, such as dopant diffusion, indirect observations of self-interstitials are more easily accessible. In our studies, we got advantages from the enhanced diffusion of boron realized by a supersaturation of self-interstitials. In particular, the broadening of very narrow B-doped (or B "delta doped") Si layers was widely used as a very sensitive marker for self-interstitials. Molecular beam epitaxy technique was extensively used to realize such B delta doped layers, about 3 nanometer wide. In addition, the same growing method was used also to produce different Si-sample structures, with various B and/or C- doped regions, tailored on purpose to conduct specific experiments.