ABSTRACT
Compliant structures have been prepared so that a thin GaAs layer (thickness about lOnm) was bonded on top of a GaAs substrate with a large twist angle (about 45°). The mechanical behaviour of such a compliant substructure was investigated by nanoindentation and the results were compared to those obtained on standard bulk substrates. A free-standing behaviour was observed under low load (< 0.25 mN). An enhancement of the plastic flow was determined above. The morphologies of relaxed InGaAs heteroepitaxial layers grown under the same conditions on standard and compliant substrates were then compared. We observed a strong decrease of the threading dislocations density in the alloy grown on the compliant substrates that could be very well correlated with the mechanical behaviour measured on these compliant substrates.
