Influence of neutral hole traps in thin gate oxides on MOS device degradation during Fowler-Nordheim stress

Abstract

A theoretical analysis of metal-oxide-silicon (MOS) device degradation due to trapping of positive charges in thin (27, 33 nm) SiO/sub 2/ gate oxides is presented. n/sup +/-polySi-gate (MOS) capacitors are stressed at a low electron injection fluence (<0.01 C/cm/sup 2/) by Fowler-Nordheim (FN) electron tunneling from the quantized accumulation layer of <100> n-Si substrate, at constant current and constant applied gate voltage. The present analysis assumes tunneling electron initiated band-to-band impact ionization (BTBII) in SiO/sub 2/, as the possible source of trapped holes during stress. The validity of the present analysis has been examined by comparing the theoretical values with the experimental data of FN threshold voltage shift /spl Delta/V/sub FN/ of Fazan et al.