Hydrogen plasma produced by a microwave multipolar reactor has been used to clean a single crystal of silicon. The substrate is kept at room tem po ar reactor has been used to clean a single treatment and then heated at 700-degrees-C. The effect of atomic species created in the plasma on the silicon surface is studied by in situ analysis (spectroscopic ellipsometry, low energy electron diffraction, and Auger electron spectroscopy) and ex situ analysis (atomic force microscopy). Quasi-instantaneous removal of carbon is demonstrated, showing the high efficiency of hydrogen plasma to remove carbon of the silicon surface. This cleaning treatment allows the obtainability of silicon surfaces exempt of contaminants (carbon and oxygen) and roughness (very low Perturbed thickness). The peaks values of the imaginary part of dielectric function of Si surface cleaned by hydrogen plasma exceed those previously reported (values of epsilon(i) at 4.25 eV=48.25). This process seems to be compatible with very large scale integrated and ultra-large scale integration technology.