A study of the electric field and temperature dependence of the breakdown a
nd quasi-breakdown phenomena is presented for 3.5 nm ultra-thin SiO2 gate o
xides. Using methodology based on the competing mecanism concept between br
eakdown and quasi-breakdown processes, quasi-breakdown activation energy as
well as acceleration factor are determined. It is demonstrated on these 3.
5nm gate oxides that the quasi-breakdown temperature activation energy is a
lmost temperature independent on the contrary to the breakdown one. Moreove
r, it has been shown that the temperature dependence of the breakdown accel
eration factor and the electric field dependence of the temperature activat
ion energy cannot be explained by a pure "E" and "1/E" models, but can be i
nterpreted by the "E" model if at least two types of molecular defect state
s are considered. (C) 1999 Elsevier Science Ltd. All rights reserved.