Light emission effect in anodic oxidation of Si

The light-emission phenomenon during anodic oxidation of Si has been studied. The emitted integrated light intensity increases exponentially with the SiO sub(2) film thickness. The emission spectrum shows two peaks related to the energies of 3.04 and 2.76 eV in the high energy region, and 1.93 eV in the low energy region. An intensity rise of the spectrum with the progress of oxidation is observed only in the low energy region. The origins of the light emission are due to the inelastic scattering of hot electrons within the light-emitting center in the SiO sub(2) layer for the low energy region and near the SiO sub(2)-Si interface for the high energy region.