Strain-compensated InGaAsP/InGaP superlattices are studied in cross section by atomic force microscopy and scanning tunneling microscopy. Undulations in the morphology of the {110} cross-sectional faces are observed, and are attributed to elastic relaxation of this surface due to underlying strain arising from thickness and compositional variations of the superlattice layers. Finite element computations are used to extract a quantitative measure of the strain variation. ©1998 American Institute of Physics.