Characterization of ultra-low-load (µN) nanoindents in GaAs(100) using a cube corner tip

In this study, nanoindentations are produced and characterized for the future patterning of nanostructures. Nanoindentation is performed on Si-doped (n-type) vertical gradient freeze (VGF) GaAs(100) and epitaxial GaAs(100) using a diamond cube corner indenter. Unlike previous research, the uniqueness of this work is in nanoindentation of GaAs at ultra-low loads ( < 400 mN). Indentations of less than 200 nm in width are produced, and the mechanical properties of the two materials including hardness and elastic modulus are determined. The smallest indentations achieved are less than 60 nm in width and less than 2 nm deep. The width, depth, shape, and volume of the indents are determined as a function of applied load using atomic force microscopy (AFM). Also, the ratio of pile-up volume to indent volume is determined. The experimental findings are discussed in relation to existing theories of indentation and for the directed self-assembly of nanostructures.