Heteroepitaxial growth on nanostructured silicon Surfaces

This phase I SBIR research effort addresses low-cost, large area development of a universal, compliantsilicon substrate technology for heteroepitaxial growth of compound semiconductor thin films. Due tolattice and thermal expansion coefficient mismatches, pseudomorphic growth beyond critical thickness is notpossible. Several models predict significant relaxation of these constraints due to various stress reliefmechanisms available in thin film and 3D nanoscale features. We propose application of 10-50-nm linewidth 3DSi structures for heteroepitaxial growth applications. By suitable choice of processing parameters, thesestructures are isolated from the thick substrate to act as highly compliant patterned thin films. The stressrelief provided by these nanoscale structures in SOI configuration has helped improve quality of GaN films. Wepropose application of these techniques for Ge and GaAs growth in collaboration with Emcore to improve space solar cells.By replacing Ge substrates with Si, substantial cost and weight reductions can be achieved. Finally, these structures arealso expected to find applications in several related material systems.Space Solar CellsLasersLight emitting diodesSi-on-insulator