Chemistry Reference
In-Depth Information
Fig. 11.2
Typical REM images of clean Si(111) surface at 900
◦
C with regular atomic steps (
a
)and
initial stage of step bunches (
b
)
Using UHV REM, the conditions under which atomically clean silicon surfaces
form were optimized for ultra high vacuum technologies. Data were obtained on
the surface structure and motion kinetics of monatomic steps that control diffusion
processes on the surface and interfaces, on homogeneous and heterogeneous sources
of monatomic steps, which are efficient sinks for adatoms on the surface of semi-
conductor substrate.
The interaction of monatomic steps with dislocations emerging at the crystal
surface was detected, which slows down the step motion velocity in the dislocation
strain field up to stopping of the step in the dislocation core [
38
,
39
].
It has been found experimentally that there are different probabilities of adatom
incorporation into the monatomic step from the side of upper and lower terraces,
which is caused by different energy barriers for adatom incorporation into the step.
It follows from the kinetics of monatomic step motion during sublimation that the
energy barrier for adatom incorporation into the step from the side of the lower
terrace is lower by 0
.
3
±
0
.
1 eV than the barrier from the side of the upper terrace.
