Physico-Chemical nanomaterials science
The effect of plasma cleaning process on wettability
of silicon (100) surface
Chodkowski M.1, Terpiłowski K.1
1 Department of Interfacial Phenomena, Institute of Chemical Sciences, Faculty of Chemistry, Maria Curie-Skłodowska University in Lublin
Sq. M. Curie-Skłodowska 3, 20-031 Lublin, Poland.
E-mail: michal.chodkowski@poczta.umcs.lublin.pl

A silicon wafer (also called a slice or substrate) is a thin slice of a crystalline silicon used for the fabrication of integrated circuits and in photovoltaics to manufacture solar cells. It undergoes many microfabrication processes, such as doping, ion implantation, etching, thin-film deposition of various materials, and photolithographic patterning.
The silicon wafer that has just been produced should have a chemically clean surface. However, it was reported that the silicon surface is covered with a thin layer of silicon dioxide [1]. This occurs in the atmosphere of air because the wafer oxidizes. Thus the process of surface cleaning plays a key role in the microfabrication processes.
There are various methods of chemical purging of silicon surface. A thin oxide layer on the silicon surface can be removed by a treatment with the HNO3, HF, and CH3COOH mixture [2] or the piranha etch. As it has been reported recently, the best method of silicon surface cleaning seems to be the solvent-reinforced de Gennes method. After its application the water contact angle value on silicon is equal to 20.7 degrees [3].
The objective of this work was to examine the effect of cold plasma cleaning of silicon (100) surface on its wettability. For this purpose oxygen or argon plasma were used. It was found that after plasma processing the water contact angle value on the silicon (100) surface decreased even to about 10 degrees.

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