title: Mechanism of atomic-scale passivation and flattening of semiconductor surfaces by wet-chemical preparations.
abstract: Atomic arrangements of Si(001), Si(110) and 4H-SiC(0001) surfaces after wet-chemical preparations are investigated with scanning tunneling microscopy. Their passivated structures as well as the surface formation mechanisms in aqueous solutions are discussed. On both Si(001) and Si(110) surfaces, simple 1 × 1 phases terminated by H atoms are clearly resolved after dilute HF dipping. Subsequent etching with water produces the surfaces with 'near-atomic' smoothness. The mechanisms of atomic-scale preferential etching in water are described in detail together with first-principles calculations. Furthermore, 4H-SiC(0001), which is a hard material and where it is difficult to control the surface structure by solutions, is flattened on the atomic scale with Pt as a catalyst in HF solution. After a mechanism is proposed based on electroless oxidation, the flattened surface mainly composed of a 1 × 1 phase is analyzed. The obtained results will be helpful from various scientific and technological viewpoints.
authors.affiliation: Department of Precision Science and Technology, Graduate School of Engineering, Osaka University, 2-1, Yamada-oka, Suita, Osaka 565-0871, Japan. arima@prec.eng.osaka-u.ac.jp
authors.forename: Kenta
authors.initials: K
authors.lastname: Arima
authors.forename: Katsuyoshi
authors.initials: K
authors.lastname: Endo
authors.forename: Kazuto
authors.initials: K
authors.lastname: Yamauchi
authors.forename: Kikuji
authors.initials: K
authors.lastname: Hirose
authors.forename: Tomoya
authors.initials: T
authors.lastname: Ono
authors.forename: Yasuhisa
authors.initials: Y
authors.lastname: Sano