Investigation of distribution and redistribution of silicon in thin doped gallium-arsenide layers grown by molecular beam epitaxy on substrates with (100), (111)Ga, and (111)As orientations

The distribution of silicon in GaAs was investigated by secondary-ion mass spectrometry (SIMS) before and after the thermal annealing of thin doped GaAs layers grown by molecular beam epitaxy on substrates with (100), (111)Ga, and (111)As orientations. The surface relief pattern of the grown epitaxial films was studied by atomic-force microscopy both inside and outside the ion-etching crater developed during the SIMS analysis. Features of the surface relief inside the crater are revealed for various orientations. Changes observed in the shape of doping profiles are explained both by the features of the development of the surface relief during the ion etching accompanying the SIMS analysis and by an accelerated diffusion of Si over the growth defects. (C) 2000 MAIK "Nauka / Interperiodica".