Chemical and electrical properties of cavities in silicon and germanium

We characterised chemical and electrical properties of cavities formed in Si and Ge by He ion implantation and annealing. Dissociation energies for Si-H and Ge-H bonds on cavity walls were determined, revealing that H chemisorption is energetically more stable than H:! gas for Si but not for Ge. Cavity walls in Si were found to trap transition metals strongly, suggesting application to impurity gettering. Measurement and modelling of cavity electrical behaviour quantified the electrical properties of these centres and elucidated surface electronic states.