Molecular beam epitaxy of silicon: Effects of heavy Sb doping

Abstract

Undoped and antimony doped Si films are deposited on large area Si substrates (51 mm diameter) by the molecular beam epitaxy (MBE) technique. The layer properties are as follows: thickness from 0.2 to 8 μm, concentration from 9 x 10 13 to 2 x 10 19 cm -3, Hall mobilities up to 1400 cm 2/ V · s. Measurements of Hall mobility, over a 4 1 2 decade variation in the resistivity, demonstrate some physical and technological problems of the Si MBE technique, such as compensation effects in undoped samples after changing of system components, or effects of heavy Sb doping. Heavily doped films are studied in detail. When varying the Sb source temperature, a limit is found above which the layer quality is drastically lowered with respect to defects, mobility and lateral doping profile. Additionally, the in-depth profile of the total Sb concentration, evaluated by neutron activation analysis, shows an anomalous concentration increase near the interface between epitaxial film and the substrate, when using large supersaturation of antimony at high source temperature.