NUCLEATION OF TWO-DIMENSIONAL SI ISLANDS NEAR A MONOATOMIC STEP ON AN ATOMICALLY PURE Si(111)-(7 x 7) SURFACE
D. I. Rogilo1, N. E. Rybin1,2, S. S. Kosolobov1, L. I. Fedina1, A. V. Latyshev1,2
1Rzhanov Institute of Semiconductor Physics, Siberia Branch, Russian Academy of Sciences, 630090, Novosibirsk, prosp. Akademika Lavrent'eva, 13
2Novosibirsk State University, 630090, Novosibirsk, ul. Pirogova, 2
Keywords: кремний, эпитаксиальный рост, двумерные островки, атомные ступени, критический зародыш, поверхностная диффузия, отражательная электронная микроскопия, silicon, epitaxial growth, two-dimensional islands, atomic steps, critical nucleus, surface diffusion, reflection electron microscopy
Abstract
The process of nucleation of 2D islands near a monatomic step at the initial stage of growing of a silicon film on the Si(111)-(7 x 7) surface is studied by means of in situ superhighvacuum reflection electron microscopy. The dependence of the depletion region width W near the step, where no islands are formed, on the deposition rate R is described by the expression W2 ∞ R-χ with the exponent χ = 1,18 and χ = 0,63 at temperatures of 650 and 680 °C, respectively. It is demonstrated that the change in χ is associated with the step structure, which ensures the transformation from the growth kinetics limited by embedding of adatoms into the step to that limited by diffusion of adatoms. A competition of the processes of nucleation and embedding into the step leads to an increase in the size of the critical particle nucleus from i = 1 far from the step to i = 3-5 near the step and to i = 6-8 on the terrace of critical width for 2D nucleation.
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