Mapping Defect Density in MBE Grown ${\rm In}_{0.53}{\rm Ga}_{0.47}{\rm As}$ Epitaxial Layers on Si Substrate Using Esaki Diode Valley Characteristics

Growing good quality III–V epitaxial layers on Si substrate is of utmost importance to produce next generation high-performance devices in a cost effective way. In this paper, using physical analysis and electrical measurements of Esaki diodes, fabricated using molecular beam epitaxy grown ${\rm In}_{0.53}{\rm Ga}_{0.47}{\rm As}$ layers on Si substrate, we show that the valley current density is strongly correlated with the underlying epi defect density. Such a strong correlation indicates that the valley characteristics can be used to monitor the epi quality. A model is proposed to explain the experimental observations and is validated using multiple temperature diode $I{-}V$ data. An excess defect density is introduced within the device using electrical and mechanical stress, both of which are found to have a direct impact on the valley current with a negligible change in the peak current characteristics, qualitatively supporting the model predictions.