Topography and lattice strain development on patterned Si surfaces

Abstract

The use of several different microscopies in the study of the development of topography on crystal surfaces during high temperature annealing is illustrated. The focus is on experiments with surfaces that have been lithographically patterned with 1- and 2-dimensional periodically repeating structures. The experiments are aimed at identifying and measuring the elementary atomic transport processes involved in material transfer at the surface. Optical diffraction, interference microscopy and scanning electron microscopies are used to study large scale features while atomic force, tunneling and low energy electron microscopies reveal details of the atomic arrangements making up these features. Particular emphasis is placed on the observation of atomic steps since it is the redistributions of atomic steps that is responsible for topography development on crystals. Atomic step motions on both 1- and 2-dimensionally periodic surfaces are interpreted in terms of surface diffusion and evaporation processes. The creation of arrays of extensive step-free areas on Si wafer surfaces is illustrated. X-ray diffraction studies of grating structures can be used to demonstrate and measure lattice strains induced, for example, by oxidation.