We have developed a predictive model of SiGe epitaxial growth from SiH4-GeH4-H2 accounting for different factors affecting the growth, including adsorption and desorption of the reactive species, surface diffusion of hydrogen adatoms, Ge surface segregation, and elastic strains in the epilayer. The gaseous species are assumed to decompose at the surface into separate atoms, H atoms covering the surface and blocking free adsorption sites while Si and Ge atoms quickly incorporating into the crystal. Fig.1 illustrates the surface kinetic mechanism we employ in the model. Note that there are many unrelated models of separate surface processes in the literature (see, for example, [1-5]), however, they do not seem to have ever been linked within a unified approach. We have unified these models using a general quasi-equilibrium approach.
Fig.1. Kinetic mechanism of SiGe epitaxial growth
Fig.2. Steady growth of pure Si or Ge from
SiH4-H2 or GeH4-H2, respectively:
growth rates vs. temperature compared to data of Li et al  (a)
and coverage of Si surface with H-adatoms vs. temperature
compared to data of Liehr et al  (b)
Fig.3. Steady growth of SiGe alloy from
growth rate vs. Ge content in the alloy
compared to data of Robbins et al  (a) a Bozzo et al (b)
and Ge content in the alloy vs. that in the gas phase
compared to data of Bozzo et al  (c)
Fig.4. Unsteady growth of SiGe alloy from
Ge proviles in the Si capping layer compared to data of Tok et al  (a)
and Ge profiles computed in "switching of" of some physical factors (b)
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Our publications on SiGe
1. A.S. Segal, S.Yu. Karpov, A.P. Sid'ko, and Yu.N. Makarov, Journal of Crystal Growth, 225, 268 (2001).
2. A.S. Segal, A.P. Sid'ko, S.Yu. Karpov, and Yu.N. Makarov, in "Fundamental Gas-Phase and Surface Chemistry of Vapor Deposition II/ Process Control, Diagnostics and Modeling in Semiconductor Manufacturing", ed. M.D. Allendorf, M.T. Swihart, and M. Meyyappan, Electrochemical Society Proceedings, 2001-13, 229 (2001).
3. A.S. Segal, A.P. Sid'ko, S.Yu. Karpov, Yu.N. Makarov, in "Semiconductor Silicon 2002 (9th International Symposium)", ed. M.T. Swihart, M.D. Allendorf, and M. Meyyappan, Electrochemical Society Proceedings, 2002-2, 567 (2002).