Formation of terraced, nearly flat, hydrogen-terminated, (100) Si surfaces after high-temperature treatment in H-2 of single-crystalline silicon

Among the processes devoted to the preparation of chemically homogeneous (100) silicon surfaces, the ones for hydrogen termination are the most promising, especially in view of the remarkable environmental stability of such surfaces. The simplest way to produce hydrogen-terminated silicon (attack of a sacrificial, thermally grown, oxide in aqueous solution of HF) results in rough, strongly heterogeneous (although with prevailing dihydride terminations) surfaces. These surfaces can, however, be flattened and homogenized by treating them in H-2 at high temperature (>850 degrees C). The morphological and chemical changes undergone by the surface during the treatment are studied ex situ (via x-ray-photoelectron spectroscopy, atomic force microscopy, scanning tunneling microscopy, infrared absorption spectroscopy in the attenuated total reflection mode, reflection high-energy electron diffraction, and thermal programmed desorption) and the mechanisms responsible for them are discussed.