Real-time stress measurements during growth of both linearly and step-graded InxAl1-xAs/GaAs metamorphic buffer layers are presented. We show that in situ stress monitoring provides information about the evolution of the film stress and surface lattice parameter, the kinetics of which cannot be fully studied using ex situ analysis. This technique may be used to help optimize the design of metamorphic buffer layers. (C) 2004 American Vacuum Society.