Preparation and Characterization of Ultraclean H:Si(111)-(1×1) Surfaces Studied by HREELS, AFM and STM-STS

Hiroki Kato; Takumi Taoka; Shozo Suto; Susumu Nishikata; Gen Sazaki; Kazuo Nakajima; Taro Yamada; Ryszard Czajka; Andrzej Wawro; Atsuo Kasuya

doi:10.1380/ejssnt.2009.557

Conference -JRSSS-8-

Preparation and Characterization of Ultraclean H:Si(111)-(1×1) Surfaces Studied by HREELS, AFM and STM-STS

Hiroki Kato, Takumi Taoka, Shozo Suto, Susumu Nishikata, Gen Sazaki, Kazuo Nakajima, Taro Yamada, Ryszard Czajka, Andrzej Wawro, Atsuo Kasuya

Author information

Hiroki Kato
Department of Physics, Graduate School of Science, Tohoku University, Japan
Takumi Taoka
Department of Physics, Graduate School of Science, Tohoku University, Japan
Shozo Suto
Department of Physics, Graduate School of Science, Tohoku University, Japan
Susumu Nishikata
Institute for Materials Research, Tohoku University, Japan
Gen Sazaki
Institute for Materials Research, Tohoku University, Japan
Kazuo Nakajima
Institute for Materials Research, Tohoku University, Japan
Taro Yamada
The Institute of Chemical and Physical Research (RIKEN), Japan
Ryszard Czajka
Institute of Physics, Faculty of Technical Physics, Poznan University of Technology, Poland
Andrzej Wawro
Institute of Physics, Polish Academy of Sciences, Poland
Atsuo Kasuya
International Advanced Research and Education Organaization, Tohoku University, Japan

Keywords: Silicon, Hydrogen termination, HREELS, Atomic force microscopy, Scanning tunneling microscopy

JOURNAL FREE ACCESS

2009 Volume 7 Pages 557-562

DOI https://doi.org/10.1380/ejssnt.2009.557

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Abstract

We review a wet chemical process to prepare the high quality hydrogen-terminated Si(111)-(1×1) surface and show that the two key issues for the high reproducibility are the etching time and the oxygen in the etching solution. We add ammonium sulfite to remove the oxygen according to the previous report [Appl. Surf. Sci. 130, 146 (1998)]. To elucidate the optimal etching time, the vibrational properties and the surface morphology are investigated by high-resolution electron-energy-loss spectroscopy (HREELS), atomic force microscopy (AFM) and scanning tunneling microscopy (STM). The HREELS spectra and images of AFM and STM reveal the precise aqueous NH₄F etching process of Si(111) and indicate the high controllability of steps and terraces with atomic scale. The surface cleanliness and morphology strongly depend on the etching time. At the etching time of 10 min, we obtain an ultra-clean and atomically ordered surface with wide terraces of 36 ± 7 nm step distance. It is confirmed by AFM and STM that the 1.0% ammonium sulfite is useful to remove dissolved oxygen in the 40% NH₄F etching solution and to prepare a high quality H:Si(111)-(1×1) surface with low density of etch pits. The measurement of scanning tunneling spectroscopy(STS) shows the Schottky diode character of the surface. This surface is well applied to the initial stages of the nano-particle and film growth of Ag atoms and Pentacene molecules. [DOI: 10.1380/ejssnt.2009.557]

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