ANALYSIS OF POSITIVE CHARGE TRAPPING IN SILICON DIOXIDE OF MOS CAPACITORS DURING FOWLER-NORDHEIM STRESS

Metal-oxide-silicon (MOS) device degradation due to trapped holes in t hermally grown thin (22-33 nm) SiO2 gate oxides under Fowler-Nordheim (FN) stress at low injected electron fluence has been analyzed theoret ically. A comparative study of degradation under various modes of FN s tressing (constant current and constant voltage) from the accumulated layer of [100] n-Si of n-PolySi gate MOS capacitors is presented. The present analysis is based on tunneling electron initiated band-to-band impact ionization in SiO2 as the possible source of generated holes. The theoretical analysis is extended with Gaussian and uniform distrib ution of trapped holes in the oxide. The theoretical results obtained from the model are in good agreement with the experimental results of FN threshold voltage shift as a function of electron fluence obtained by Fazan et al. (C) 1997 Elsevier Science Ltd.