Modeling of strain partitioning in nanoheterostructures

In this thesis, a self-consistent model is presented to describe the concepts of strain partitioning in nanoheterostructures using the formalism developed by Zubia (2002). The model predicts enhanced 3D strain partitioning in nanoheterostructures when the nanostructure aspect ratio is increased above 1:10. Importantly, the new strain partitioning model converges to the planar model when the structure diameter tends towards infinity. Hence this model is applicable to planar (conventional and compliant) and to other past works in the literature. This paper will also discuss the variation of strain energies and critical thickness in nanoheterostructures. It is predicted that the total strain energy decreases by 50% of its planar counter-part if the aspect ratio is increased to 1:10. Analogous to the critical thickness (hc), we define and calculate a critical nanostructure diameter, (21c), below which defect free heteroepitaxial growth occurs. The critical thickness is calculated using a two-step approach, incorporating initially an energy balance criterion (People and Bean, 1985) and then a force balance criterion (Mathews and Blakeslee, 1974). (Abstract shortened by UMI.