  We consider the possibility that a right-handed sneutrino can serve as the
source of energy density perturbations leading to structure formation in
cosmology. The cosmological evolution of a coherently oscillating condensate of
right-handed sneutrinos is studied for the case where reheating after inflation
is due to perturbative inflaton decays. For the case of Dirac neutrinos, it is
shown that some suppression of Planck scale-suppressed corrections to the
right-handed neutrino superpotential is necessary. cH^2 corrections to the
sneutrino mass squared term must also be suppressed during inflation (|c| <
0.1), in which case, depending on the magnitude of |c| during inflation, a
significantly blue (if c > 0) or red (if c < 0) perturbation spectrum is
possible. R-parity must also be broken in order to ensure that the Universe is
not overclosed by LSPs from the late decay (at temperatures 1-10 MeV) of the
right-handed sneutrino condensate. The resulting expansion rate during
inflation can be significantly smaller than in conventional supersymmetric
inflation models (as low as 10^6 GeV is possible). For the case of Majorana
neutrinos, a more severe suppression of Planck-suppressed superpotential
corrections is required. In addition, the Majorana sneutrino condensate is
likely to be thermalised before it can dominate the energy density, which would
exclude the Majorana right-handed sneutrino as a curvaton.
