Electronic states related to dislocations in silicon

Dislocations and impurities in silicon, even though studied since many years, are now subject of a renewed interest. Moreover, many question related to dislocation- related electronic states remain still unsolved. The present contribution reviews several results, obtained by the authors, on dislocation impurity interactions and their effects on the electronic properties of defect states in silicon. Dislocations introduced by plastic deformation and oxygen precipitation in p-type Czochralski (Cz) silicon have been investigated by junction spectroscopy methods. A deep hole trap, named T1, has been associated to dislocationrelated impurity centers, while additional deep traps have been related to contamination by grown-in transition metals and to clusters involving oxygen atoms. Moreover, experimental results obtained by junction spectroscopy assessed the existence of dislocation related shallow states. These were found to be located at 70 and 60 meV from the valence and conduction band edge, respectively