ssed in chapter 4. 3.10. LOW DOSE AND HIGH DOSE REGIMES IN THE SIMPLIFYING CASE OF INTERFACE TRAPPING This model has been widely used in the literature for more than 25 years to account for charge trapping in thermal oxides. Although we know for 15 years that it is not completely true, the most often used hypothesis is that these oxides only possess hole traps. We therefore neglect electron trapping in neutral traps, and consider that electrons are only able to recombine with trapped holes. The hole traps are supposed to be entirely located at the Si/SiO2 interface. The equations in this case are simplified compared to the previous case, since we consider that the carriers generated by irradiation can move through the oxide without trapping in the bulk, and only be trapped at the interface. By taking recombination phenomena into account, the evolution equation for charged traps at the III-32 interface can be written: where NTPS now represents the trap density at the interface and NTPS is the fraction of charged traps. Note that we now take the recombination of trapped holes with free electrons into account, as one goal is to account for saturation behavior when a steady state occurs between the effects of the hole and electron fluxes. To get the expression of the current at the interface, we need the integration of continuity and transport equation in the volume of oxide. From the hypothesis, no deep trap NTP is supposed to exist in the volume, SO that carriers will be only subjected to be self-trapped of recombined. We shall gather all this physics into a first-order kinetics, characterized by a lifetime n (for electrons) and p (for the holes). Note that as no deep traps exist in the volume, it is likely that the value of p identifies with the "free" hole lifetime p0 (see section 3.6.3), and SO does Up with . This gives a value of Up p of nearly 10-12 cm2 V-1, used in many models since the 60s and relatively independent of the temperature. (The situation is not as clear for choice of a value for the electrons.) 