A new wet treatment was used to prepare a Si(1 0 0) wafer surface and its surface morphology, atomic arrangement, and chemical structure over a large area were characterized by atomic force microscope, ultra-high vacuum scanning tunneling microscope, and Fourier-transform infrared spectroscopy with attenuated total reflection mode, respectively. An atomically smooth Si(1 0 0) wafer surface with a step/terrace periodic structure was prepared using a hot ammonium fluoride (NH4F) treatment at 76 degreesC. The surface exhibited mainly characteristic SiH2 surface termination structure, but was missing the atomic low 2 x 1 superlattice. A precisely controlled surface would be useful for Si ultra-large-scale integrated circuit (ULSI) device production. (C) 2004 Elsevier B.V. All rights reserved.