Molecular Beam Epitaxy (MBE) is a leading technique for growing
semiconductor devices. It is also likely to become important in the
production of new devices for the magnetic storage industry.
A key aspect that limits the performance of MBE is the roughening
of surfaces during the growth process. To better understand this effect we participate in a joint experimental and theoretical effort
that is studying the growth of iron on nearly perfect iron surfaces.
This system is relevant to future magnetic devices, and it has proven
to be a good model
system to understand the general behavior of surface roughness during
MBE growth.
We have carried out
simulations of the growth on an 8-node workstation cluster using
PVM-based
software. The figure compares some of our results with experiment.
(a) an STM image of 10 monolayers of iron grown on an iron
whisker at 20 degrees C. The image is 100x100 nm and the gray scale
covers a range of 0.9 nm where white indicates higher portions of the
surface.
(b) a detail of the data in (a), shown as a contour plot. Solid lines indicate equiheight contours, with the heavy line at
the mean height.
(c) a corresponding height profile
simulated with a particular continuum growth equation. The comparison
of the these figures and other aspects of the growth show that the
growth process is more complicated than has been assumed in previous
simulations. It also shows that it is likely that growth in many
systems can likely be understood in the same context.
