Scanning tunneling microscopy study of the growth and self-organization of Ge nanostructures on vicinal Si(111) surfaces

Abstract

The initial stages of Ge growth on Si(111) vicinal surfaces tilted in the [$\overline 1 \overline 1 2$] and [$11\overline 2$] directions were studied in situ in the temperature range 350–500°C using scanning tunneling microscopy. It was shown that, at low Ge deposition rates of 10⁻² to 10⁻³ BL/min, ordered Ge nanowires can form on surfaces tilted in the [$\overline 1 \overline 1 2$] direction under conditions of step-layered growth. The height of a nanosized Ge wire is one or three interplanar distances and is determined by the initial height of a silicon step. It was established that, during epitaxial growth, steps with a [$11\overline 2$] front are replaced by steps with a [$\overline 1 \overline 1 2$] front. As a result, the step edge is serrated and the formation of smooth nanosized Ge wires uniform in width is hampered on the serrated Si(111) surfaces tilted in the [$11\overline 2$] direction.