  We have revealed that the barrier-tunneling process in non-integrable systems
is strongly linked to chaos in complex phase space by investigating a simple
scattering map model. The semiclassical wavefunction reproduces complicated
features of tunneling perfectly and it enables us to solve all the reasons why
those features appear in spite of absence of chaos on the real plane.
Multi-generation structure of manifolds, which is the manifestation of
complex-domain homoclinic entanglement created by complexified classical
dynamics, allows a symbolic coding and it is used as a guiding principle to
extract dominant complex trajectories from all the semiclassical candidates.
