PROJECT TITLE :

Separation of Front and Backside Surface Recombination by Photoluminescence Imaging on Both Wafer Sides

ABSTRACT:

During this paper, we present a technique to separate the front and also the backside surface recombination based mostly on 2 photoluminescence pictures: one taken from the front aspect of the wafer and one from the backside. We use a 790-nm laser with a penetration depth in silicon of only eleven μm. At such a shallow charge carrier generation, the surface recombination of the illuminated facet affects the minority carrier density to a greater extent than the recombination of the nonilluminated side. To utilize this result, we have a tendency to calculate the ratio of the front aspect and the rear side lifetime image. This ratio image allows an simple distinction not only of surface defects from bulk defects but of front surface recombination from back surface recombination similarly. With a simple calculation, even quantitative surface recombination velocities will be obtained.