The Interaction of Water with Solid Surfaces: Fundamental Aspects Revisited

Electrochemistry of redox-active self-assembled monolayers

In situ scanning tunneling microscopy in electrolyte solutions

The general concepts governing the electrochemical deposition of metal films onto semiconductors are discussed Deposition onto semiconductor surfaces is complicated due to the band structure of the semiconductor, which affects both the thermodynamics and the kinetics of metal deposition processes The influence of the potential distribution at the semiconductor/solution interface on the charge transfer mechanisms involved in deposition of metals is discussed Models for electrochemical nucleation and growth are described and the influence of the unique physical properties of semiconductors is analysed Finally, we present recent results for electrochemical deposition of gold, copper and platinum onto n-type silicon

https://iopscience.iop.org/article/10.1088/0022-3727/31/16/001/pdf

Electrochemical deposition of metals onto silicon

Morphology of hydrogen-terminated Si(111) and Si(100) surfaces upon etching in HF and buffered-HF solutions

Aqueous HF etching of silicon surface removes surface oxide, leaving a silicon surface terminated by atomic hydrogen. We studied the effect of the immersion in water, following HF etching, on the surface hydride structure and flatness, by measuring Si‐H stretching vibration using infrared absorption spectroscopy. Immersion at 20 °C flattens the Si(111) surface, which is atomically rough just after etching, to some extent. Boiling water (100 °C) produces an atomically flat surface homogeneously covered with silicon monohydride (—SiH) normal to the surface and free of oxidation. The surface has a low defect density of less than 0.5%.

Homogeneous hydrogen-terminated Si(111) surface formed using aqueous HF solution and water

Aqueous HF etching of the silicon surface removes surface oxide, leaving a silicon surface terminated inhomogeneously by silicon mono-, di-, and trihydrides. We studied the effect of the immersion in water following the HF etching, on the surface hydride structure on Si(111), by measuring Si-H stretching vibration using infrared absorption spectroscopy. Immersion in boiling water (100°C) for 600 s produces a surface homogeneously terminated with silicon monohydride normal to the surface and free of oxidation. We concluded that water can remove silicon dihydride and trihydride and leave a silicon surface terminated with monohydride. The homogeneous surface has a low defect density of less than 0.5%.

https://iopscience.iop.org/article/10.1143/JJAP.30.3575/pdf

Silicon-Monohydride Termination of Silicon-111 Surface Formed by Boiling Water

We examined the infrared spectrum of Si(111) after terminating its surface with silicon monohydride and immersing it in various concentrations of HF solution to induce fluorine adsorption. After immersion in HF solution, a part of the silicon monohydride surface was etched and (100), (010) and (001) steps composed of strained dihydrides appeared. The silicon-hydrogen stretching frequency for the monohydride was shifted by the fluorine adsorption. Angle-resolved X-ray photoelectron spectroscopy revealed that fluorine penetrates the silicon lattice as well as exists close to the surface. We conclude that fluorine does not terminate the surface silicon dangling bond but inhabits interstitial sites just below the silicon surface.

Satoru Watanabe

Papers

Homogeneous hydrogen-terminated Si(111) surface formed using aqueous HF solution and water

Silicon-Monohydride Termination of Silicon-111 Surface Formed by Boiling Water

Fluorine Adsorption and Etching on Si(111):SiH Surface during Immersion in HF Solution

Silicon-Monohydride Termination of Silicon-(111) Surface Formed by Boiling Water