Plastic relaxation of metamorphic single layer and multilayer InGaAs/GaAs structures

The plastic relaxation of multilayer structures of strained InGaAs grown above critical thickness on GaAs is reported and compared with the relaxation of single layers and with theory. We show that a composite structure, taken as a whole, follows the same relaxation law as observed in single layers. However, departures of the strains of some component layers from theory show that misfit dislocations are easily pinned at an interface. Implications for the design of relaxed buffer layer growth are discussed.