Formation and Structural Features of Silicon Quantum Dots in Germanium
N. P. Stepina1, A. F. Zinov’eva1, A. S. Deryabin1, V. A. Zinov’ev1, V. A. Volodin1, A. A. Shklyaev1, A. V. Dvurechenskii1, S. V. Gaponenko2
1Rzhanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, pr. Akademika Lavrent’eva 13, Novosibirsk, 630090 Russia
2Institute of Physics, National Academy of Sciences of Belarus, pr. Nezavisimosti 68, Minsk, 220072 Belarus
Keywords: quantum dots, silicon, germanium, hydrogen
Abstract
The formation of Si quantum dots on Ge is studied. Fundamental differences were found between the nucleation and growth of quantum dots on substrates with different orientations, related to both the formation of a SiGe solid solution layer and the shape of quantum dots. The temperature interval of formation of Si nanocrystals on Ge (111) is determined. It is shown that a change in the epitaxy temperature from 480 to 400 ºC increases the silicon content in quantum dots from 58 to 75 %. The effect of surfactants (in particular, hydrogen) on the nucleation and growth of silicon nanoislands is analyzed, showing that the use of hydrogen as a surfactant leads to a decrease in the size of quantum dots and a substantial increase in their density. The observed effects are attributed to the suppression of surface diffusion of atoms in the presence of hydrogen.
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