  We analyze a class of 5D models where a 3 brane is generated by a bulk scalar
field non minimally coupled to gravity. We show that perturbative stability of
such branes is normally guaranteed although non minimal couplings are not
innocuous in general. After the physical states are identified the linearized
equations for propagating modes are evaluated into a Schroedinger form and
supersymmetric quantum mechanics provides the absence of tachyons. The spectrum
contains a tower of spin 2 and spin 0 fields with continuous masses starting
from zero ones. For regular geometries the scalar spectrum contains a state
with zero mass which is always non normalizable. The propagating massive scalar
states are repelled off the brane due to a centrifugal potential.
