Capture and emission of electrons at 2.4-eV-deep trap level in SiO2films

Abstract

Capture, photoionization, and impact-ionization cross sections for a 2.4-eV-deep electron trapping center in the silicon-dioxide layer of a metal-oxide-semiconductor structure have been determined using the photoinjection-photodepopulation technique. The electric field dependence of both capture and impact-ionization cross sections have been determined for accelerating fields in the range 0.1-1.0 MV/cm. Capture cross sections are of order ${10}^{\ensuremath{-}14}$ ${\mathrm{cm}}^{2}$ and uv photoionization cross sections greater than ${10}^{\ensuremath{-}18}$ ${\mathrm{cm}}^{2}$. High-field impact-ionization rates are 1-10 ${\mathrm{cm}}^{\ensuremath{-}1}$ for filled trap densities of order 5 \ifmmode\times\else\texttimes\fi{} ${10}^{13}$ ${\mathrm{cm}}^{\ensuremath{-}3}$.