  Superconductor-insulator transition driven by the decreasing concentration of
electrons $n$ is studied in the case of the disorder potential created by
randomly positioned charged impurities. Electrons and Cooper pairs (formed by
an non-Coulomb attraction) nonlinearly screen the random potential of
impurities. Both electrons and Cooper pairs can be delocalized or localized in
the resulting self-consistent potential. The border separating the
superconductor and insulator phases in the plane of the concentration of
electrons and the length of the Cooper pair is found. For a strong disorder the
central segment of this border follows the BEC-BCS crossover line defined for a
clean sample.
