Synchrotron Radiation-Assisted Etching of Silicon Surface

Abstract

The photo-assisted etching of heavily phosphorous-doped polycrystalline silicon by chlorine was studied using synchrotron radiation as an extreme ultraviolet (EUV) light source. The quantum yield for the removal of the Si atoms at a chlorine pressure of 0.3 Torr was found to be about 0.5% photon -1 using the Ti-filtered light, which is mostly in the EUV region, 1-20 nm. Formation of electronically excited Cl + ions upon EUV irradiation was confirmed by emission spectroscopy. Negative bias applied to the Si crystal was found to increase the etch rate.