Discontinuous yield in InGaAs thin films

Discontinuous yield during nanoindentation is observed on a wide range of materials and has generally been associated with materials having a low dislocation density before deformation. The dislocation density of InxGa1 − xAs films grown on GaAs can be varied by changing the atom fraction of In and thereby the lattice mismatch between substrate and film. Using TEM and by varying the dislocation density by means of indentations with different spacings, the probability of a discontinuous yield event in InGaAs was found to correlate with the initial dislocation density estimated from the misfit.