Direct measurement of the energy distribution of hot electrons in silicon dioxide

The energy distribution of hot electrons in high-field stressed amorphous silicon dioxide (SiO2) films have been measured using a vacuum emission technique. Electrons having average energies ≳2 eV and an energy relaxation length of λ≊32 Å are observed at all fields studied (≳ 2 MV/cm). However, contrary to previous theoretical expectations, the majority of carriers in the distribution remains stable at all fields. The results are in agreement with other recent experiments (electroluminescence and carrier separation) which only measure the average energy of hot electrons in SiO2 and with recent Monte Carlo transport calculations which include scattering by both optical and acoustic phonon modes. Results for varying SiO2 thickness, metal gate thickness, oxide composition, and metal gate composition will be discussed.