  The interference induced transverse negative magnetoresistance of
GaAs/InGaAs/GaAs quantum well heterostructures has been studied in the presence
of strong in-plane magnetic field. It is shown that effect of in-plane magnetic
field is determined by the interface roughness and strongly depends on the
relationship between mean free path, phase breaking length and roughness
correlation length. Analysis of the experimental results allows us to estimate
parameters of short- and long-range correlated roughness which have been found
in a good agreement with atomic force microscopy data obtained for just the
same samples.
