Contactless Evaluation of the Surface Recombination Property of Silicon with an Ion-Implanted Layer

The surface properties of silicon are investigated by the noncontact laser (λ=774nm)/microwave method. The effective surface recombination velocity (Seff) at an n+n high-low junction interface is estimated by fitting the experimental decay curve for excess carriers with the theoretical decay curve. The results show that Seg decreases as the dopant concentration increases and that Seff at the n+n high-low junction formed with a dose of 1×l015 ions/cm2 has values lower than 1 cm/s. And it is shown that Scff is inversely proportional to the potential barrier height of the n+n high-low junction. Similar results are obtained using an N2 laser (λ=337.1nm) instead of a laser diode (λ=774nm, 904nm) as a carrier excitation pulse source.