Stress development during annealing of self-assembled InAs/GaAs quantum dots measured in situ with a cantilever beam setup

We have investigated the coarsening of InAs quantum dots (QDs) in real time by measuring the stress evolution using an in situ cantilever beam setup. During deposition of InAs QDs, stress is accumulated, which then relaxes during subsequent annealing. Models based on different mechanisms for Ostwald ripening are fitted to the stress relaxation curves. A model describing ripening limited by diffusion along dot boundaries yields a good fit for annealing at 440 °C. For annealing at 470 °C, the relaxation curve can be fitted very well with a model in which ripening is controlled by attachment/detachment of atoms on the dot surface.