Real time monitoring of the interaction of Si (100) with atomic hydrogen: The “H-insertion/Si-etching” kinetic model explaining Si surface modifications

The interaction of $p$- and $n$-type crystalline silicon [c-Si (100)], with atomic hydrogen produced by a remote radiofrequency (13.56 MHz) $H2$ plasma has been investigated in real time using in situ spectroscopic ellipsometry. The effects of substrate doping, temperature and time on the c-Si surface modifications are discussed. A thicker hydrogenated surface layer forms for $n$-type Si. This hydrogenated layer is subsequently etched by further exposure to hydrogen. A kinetic model based on the competition between hydrogen insertion and silicon etching is proposed to explain modifications of c-Si, and the rate constants of the hydrogen insertion and silicon etching processes are determined.