Compliant structures were fabricated in which a thin GaAs layer (10 to 20nm) was bonded onto a GaAs substrate at a large (37°) twist angle. This angle was chosen so that the energy of the boundary, a coincident boundary of the form Σ = 5 (001), was minimized. The structure of the interface was characterized and the onset of plasticity in the compliant sub-structure was investigated by using nano-indentations which permitted the low-load deformation regime to be observed. The results were compared with those obtained under the same conditions, but using a bulk GaAs substrate. No plastic zone was observed, using transmission electron microscopy, in the compliant structure under loads below 0.25mN. Plastic deformation was observed in the bulk substrate under the same loads. At higher loads (2mN), plastic flow enhancement was observed in the compliant structure. The results were explained in terms of the dislocation arrangements that were observed in the plastic zones.

Onset of Plasticity in a Σ = 5 GaAs Compliant Structure. E.Le Bourhis, G.Patriarche: Philosophical Magazine Letters, 2001, 81[12], 813-22