GALLIUM DOPING OF SILICON MOLECULAR-BEAM EPITAXIAL LAYERS AT LOW-TEMPERATURES AND UNDER SI+ ION-BOMBARDMENT

Gallium doping of silicon molecular beam epitaxial layers is investigated in the temperature range between 550 and 300°C. Down to about 450°C, the incorporation behaviour can be described by a simple kinetic model. Deviations from an activated behaviour are indicative of kinetic limitations. At lower temperatures a complicated incorporation dynamics with two distinct regimes is observed. Doping by secondary implantation is investigated as a function of ion energy. A significant implantation yield is observed at low energies, while at higher energies sputter desorption of the gallium adlayer becomes dominant. Implications of the results for more efficient gallium doping techniques are discussed. © 1990.