Observation of Si(1Â 0Â 0) surfaces annealed in hydrogen gas ambient by scanning tunneling microscopy

We investigated the cleaning process of Si(1 0 0) surfaces by annealing in H2 gas ambient following chemical treatments by scanning tunneling microscopy. We observed the monohydride Si structure: Si(1 0 0):2 × 1-H on the surfaces annealed at 1000 °C in 2.5 × 104 Pa H2 gas ambient without conspicuous contaminants. On the sample annealed for 10 min or longer times, well-defined Si(1 0 0) structures with alternating SA and SB steps were observed, whereas the initial roughness still remained on the surfaces annealed for only 5 min.