Si adatom surface migration biasing by elastic strain gradients during capping of Ge or Si1−xGex hut islands

摘要: Hut cluster formation during Ge or Si1−xGex solid source molecular beam epitaxial growth on Si(001) is a well-known kinetic pathway for partial strain relief. It results in undulated morphologies with {105} facets allowing a∥ lattice parameter relaxation the island apexes. Here, we show how subsequent Si coverages, grown at 500 °C, avoid being tensile strained and impede further increase of stored elastic energy. Dominant inhomogeneous surface diffusions take place as proven by marker technique able to provide transmission electron microscopy high-resolution images initial morphology stages reflection high-energy diffraction examinations. This mechanism prevails high enough rates, quench lateral diffusion limit chemical Mediated stress variations noncapped curvatures, depleted from top islands accumulates troughs ripples where it ac...