Abstract
The step flow dynamics during homoepitaxial
diamond deposition on vicinal {001} diamond surfaces in the presence of
nitrogen impurities in the gas phase is investigated by experiments as
well as by computer simulations. The adsorption of impurities on the diamond
surfaces leads to step bunching, whereby complex two-dimensional patterns
are formed. A mesoscopic Monte Carlo model is used to study this effect,
whereby line tension, anisotropy in step propagation, roughness of steps
and impurity strength are introduced on a physical basis. The similarity
between experimental results and the step configurations resulting from
simulations is remarkable. Furthermore, the coexistence of both step bunching
and an increased growth rate upon nitrogen addition is explained by the
fact that nitrogen on the surface has a different effect on the diamond
growth than sub-surface nitrogen. This study gives a demonstration of a
fruitful co-operation between computer simulations and real world experiments,
which leads to a better understanding of the physical processes occurring
during crystal growth. (C) 2000 Elsevier Science S.A. All rights reserved.