A.I. Il’in, A.V. Chernykh and C.V. Dubonos

A.I. Il’in, A.V. Chernykh and C.V. Dubonos, Institute of Microelectronics Technology & High Purity Materials, Russian Academy of Sciences

Large island-crystallites of micron size obtained from thermal deposited continuous Bi and Bi—Sb(20%) films on amorphous SiO₂/Si substrate during ultrahigh vacuum annealing at 240-270 ^oС have been studied by scanning electron and atomic-force microscopes. Conglomerations of islands with various in-plane orientations and distinct faceting have been observed to form fist followed by separate islands with the preferred (111)_Bi orientation parallel to the substrate surface. Sb doping of Bi promotes the formation of large single crystals and decreases their faceting. A truncated polyhedral pyramid proved to be the most common and stable form of the islands. The evolution of island size and orientation during annealing is accounted for by the dilution of disadvantageously oriented and small grains due to the diffusion of atoms on the substrate surface, and the increase in the height is attributable to the successive growth of the most densely packed facets of the grains. Single crystal structures oriented relative to the faceting planes have been fabricated from the largest separate grains with a lateral size of 500 to 1500 nm for electron transport measurements by atomic-force and electron microscopes, electron lithography and ion beam etching.

Bismuth, thin films, electron-beam lithography, atomic-force microscopy, microstructures.

russian