  We present Monte Carlo simulation data obtained for the annealed surface
GaN(0001) and compare them with the experimental data. High temperature
particle evaporation is a part of substrate preparation processes before
epitaxy. The ideal surface ordering expected after such heating is a pattern of
parallel, equally distanced steps. It appears however, that different types of
step structures emerge at high temperatures. We show how the creation of
characteristic patterns depends on the temperature and the annealing time. The
first pattern is created for a very short evaporation time and consists of
rough steps. The second pattern built by curly steps is characteristic for
longer evaporation times and lower temperatures. The third pattern, in which
steps merge together creating bunches of steps happens for the long enough
time. At higher temperatures, bunches of steps bend into the wavy-like
structures.
