Influence of In
on the surface morphology of HVPE grown GaN
C.E.C. Dam, P.R. Hageman, W.J.P. van Enckevort, T. Bohnen and P.K.
Larsen
Abstract
In this paper, a study is presented on the effect of In on the surface
morphology of GaN grown by HVPE. Experiments are performed with N2 and
H2 as the carrier gasses, both with and without In present in the
reactor. The adding of In increases the morphological quality of the
grown layers; this effect is most strongly observed for N2 as the
carrier gas. It is found that adding In reduces the growth rate and
also increases the steepness of the growth hillocks on the surface. The
step velocity, which is calculated from hillock slopes and the growth
rate, decreases upon adding In. Without In, trails are visible across
the surface where steps are distorted by passing a dislocation outcrop.
With In present this pinning is still present, however, the trails do
not form. Two possible explanations for this phenomenon are an
increased surface diffusion due to a mono- or bi-layer of In on the
surface and the slower step motion when In is present.