Enhanced room temperature oxidation in silicon and porous silicon under 10 keV x-ray irradiation

We report the observation of enhanced oxidation on silicon and porous silicon samples exposed in air ambient to high-dose-rate 10 keV x-ray radiation at room temperature. The evolution of the radiation-induced oxide growth is monitored by ellipsometry and interferometric reflectance spectroscopy. Fourier transform infrared FTIR spectroscopy shows the emergence of Si–O–Si stretching modes and corresponding suppression of SiHx and Si–Si modes in the porous silicon samples. The radiation response depends strongly on initial native oxide thickness and Si–H surface species. The enhanced oxidation mechanism is attributed to photoinduced oxidation processes wherein energetic photons are used to dissociate molecular oxygen and promote the formation of more reactive oxygen species. © 2010 American Institute of Physics. doi:10.1063/1.3512965