Chemistry Reference
In-Depth Information
Fig. 11.6
REM images of consequent stages of step bunching induced by gold deposition of
0.28ML on Si(111) surface at 870
◦
C under DC heating in the step-down direction
we showed that step bunches transform into regular steps under gold deposition
at extremely high rates at temperature of 1260
◦
C in the case of heating electrical
current passing in the step-down direction.
Figure
11.7
represents series of REM images which illustrated the Si(111) sur-
face morphology transformations after deposition of 0.7ML of gold and subsequent
annealing at 900
◦
C for the step-up current direction. After gold deposition on the sil-
icon surface at 500
◦
C, the evaporator was switched off and one can see appearance
of additional RHEED patterns corresponded to the (
√
3
×
√
3) reconstruction. Then
the sample temperature was increased to 900
◦
C and the system of step bunches was
observed similar to the initial surface before gold deposition (Fig.
11.7
a). At once no
additional reflections corresponding to surface reconstruction were observed at the
RHEED pattern at this temperature. During high-temperature annealing a decreas-
ing of gold concentration should be due to gold evaporation and gold dissolving
