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

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.