  We calculate the transmission coefficient for a particle crossing a potential
barrier in monolayer graphene with Rashba spin-orbit coupling and in bilayer
graphene. We show that in both the cases one can go from Klein tunneling
regime, characterized by perfect normal transmission, to anti-Klein tunneling
regime, with perfect normal reflection, by tuning the Rashba spin-orbit
coupling for a monolayer or the interplane coupling for a bilayer graphene. We
show that the intermediate regime is characterized by a non-monotonic behavior
with oscillations and resonances in the normal transmission amplitude as a
function of the coupling and of the potential parameters.
