Decay of isolated hills and saddles on Si(001)

Abstract

Wediscuss the high temperature decay of isolated hills and saddle points on Si(001). Using in situ dark-field imaging in low energy electron microscopy, we track the movement of individual steps during high temperature annealing.Wefind different temperature dependent decay rates for the top of the hill compared to a saddle point with low step density that is present in the vicinity of the hill. The decay rate of the hill is always higher than the decay rate at the saddle. The two rates converge with increasing temperature and become equal at temperatures above 1060 °C.Wealso report an alternating fast and low decay rate for the layer-by-layer decay of the hills. This surprising finding is independent of temperature and is explained by macroscopic strain in the sample.