The theoretical studies presented in this paper concern the influence
of the atomic structure of the tip on the tunneling of electrons betwe
en the tip and the sample in STM. This problem has been discussed for
the system formed by Al(001) surface and aluminium tip, where differen
t geometries of the tip were taken into consideration. The obtained re
sults have shown how various geometries of the tip induce considerably
different STM images of the surface.