Influence of copper on the diffusion length of the minority carriers in devices based on n-type Si/SiO2

• Detrimental properties of Cu on the diffusion length of n-type Si were investigated.
• The reduction of Lp was correlated with the presence of Cu-related defects.
• Two Cu-related defects E210 and E330 were observed.
• E210 was attributed to Cu-related precipitates.

In the present study we demonstrate that the introduction of Cu leads to a significant reduction of the diffusion length in n-type Si/SiO2 structures. Using capacitance versus time measurements we show that the quasi-neutral generation mechanism is not dominant in Cu-contaminated samples at 90 °C. We correlate this behaviour with Cu-related defects which act as strong recombination centres in Si. Their electrical properties are determined and their origin will be discussed.