PNNL

Abstract

The nucleation and growth of Al on 7×7 and v3×v3 R30 Al reconstructed Si (111) that result in strain-free Al overgrown films are grown with an atomically abrupt metamorphic interface are compared. The reconstructed surfaces and abrupt strain relaxation are verified using reflection high energy electron diffraction. The topography evolution is studied with atomic force microscopy. The growth of Al on both the surfaces exhibit 3D island growth, but the island evolution of growth is dramatically different. On the 7×7 surface, mounds form uniformly distributed across the substrate, and growth appears to proceed uniformly. Alternatively, on the v3×v3 R30 surface, Al atoms exhibit a clear preference to form mounds near the step edges. During Al growth, mounds increase in size and number, expanding out from step edges until they cover the whole substrate.