Abstract:
It is well known that screw dislocations
are step sources that allow crystals to grow at low driving forces. Growth
is accelerated at the outcrop of a screw dislocation generating a spiral
hillock. This makes the intersection of a screw dislocation and a crystal
surface a so-called velocity source. In this paper the interaction between
dislocation growth, 2D-nucleation and misorientation step flow is investigated
for a wide range of driving forces by means of Monte Carlo simulations
of growth of the Kossel (100) surface. The interactions between the different
growth mechanisms are shown to agree with a general model for velocity
source behavior, which allows for a simple analytical expression of the
growth rate. This expression can be used in a continuum description of
crystal growth. Finally, dislocation etching is studied and compared with
dislocation growth. (C) 2000 Elsevier Science B.V. All rights reserved.