ed in the preceding sections, we can try to estimate the characteristic parameters of the oxide traps. The reasoning is made then in terms of net equivalent charge projected at the Si/SiO2 interface, which corresponds to what is measured experimentally. We therefore use the equation of the voltage shift due to a trap distribution at the interface in the regime of strong applied electric field (i.e. with fh(E) III-44 in which we further assume F(E) 0. By differentiating with respect to D, we can write: The plotting of In(-d Vo toto as a function of dose leads to a separate extraction of the capture cross section and of the net equivalent charge at the interface, by determining the slope of the obtained curve and its intercept with the y-axis. For hole traps, this procedure of parameter extraction is only valid when the internal field is not too significantly disturbed by the trapped charge, i.e. in the low dose regime with a large applied electric field. When charge trapping occurs at the Si/SiO2 interface, the extraction of trap parameters is straightforward from the set of Eqns. (75) and (76) after extraction of the Vot component, It becomes more difficult when charge trapping takes place in the oxide bulk (Eqn. 52 or 57). However this method is limited, because it only gives access to the product of the capture cross section by the trap density. The evaluation of the trap density usually requires to push irradiation in the saturation region, where internal electric field is distorted by the space-charge effect due to the trapped charges itself. Anyway, to assess this self-consistent effect, it is necessary to use a model of trap profile. 3.15. CASE WHERE TWO TYPE OF TRAPS ARE PRESENT 3.15.1. CASE OF UNIFORM DISTRIBUTION OF TRAPS In the same manner as before, we can calculate the voltage shift associated with a negative charge trapped on uniformly distributed electron traps, for a positive applied bias In the case of uniform trapping, we must go back to differential equations (boundary conditions have to be exch