It is shown that the relationship limn→S ∂I sc/ ∂n= (s/D) Isc connecting the normal derivative of the short circuit Isc generated by an electron or ion beam in a P-N junction with the surface recombination velocity s and the diffusion constant D is valid for arbitrary junction geometries, arbitrary doping profiles, and arbitrary distributions of recombination centers, provided that (1) low-level injection prevails and (2) the radius of the beam-semiconductor interaction volume is small compared to the local diffusion length. It thus becomes possible to study the surface recombination velocity of the front surface of a highly nonuniformly doped shallow junction representative of, for instance, a solar cell by means of an ion beam.
