Why Si(100) steps are rougher after etching

WILLIAMS, F J; ALDAO, C M; GONG, Y; WEAVER, J H

PHYSICAL REVIEW B

AMER PHYSICAL SOC

Año: 1997 vol. 55 p. 13829 - 13834

1098-0121

Scanning tunneling microscope images of halogen-etched vicinal Si(100)-2􏰾1 show that Si removal in- creases the step roughness relative to the clean surface. We compare the kink length, kink separation, and deviation-deviation correlation function for steps of clean surfaces and for surfaces etched at 700 and 900 K. The changes in step pattern at 700 K are well reproduced by Monte Carlo simulations, in which attaching and detaching events for Si blocks of two dimers are described according to the energetics deduced for the clean surface, with account taken of the etching-induced change in the ratio between attaching and detaching events. The results at 900 K show additional contributions related to breakthrough of retreating steps and terrace etch pits.