any physical process involved at the trapping site. On the other hand, the field vanishes to less than 70 kV/cm at the negative electrode (Field-Collapse) SO as to fulfill the integral condition of developing the externally imposed -5 Volts. Conclusions and methods used in 1D used are useful as a start for conveniently handling more complex 2D and 3D simulations. In the following, other causes of annealing of the trapped charge are addressed. III-61 5. DETRAPPING AND TIME-EVOLVING EFFECTS 5.1. ANNEALING, REVERSE-ANNEALING AND REBOUND In the prior discussion, we have treated the trapped charge as being stable in time after the irradiation. This is only partially true and these effects are permanent only in appearance. We observe that a part of the trapped charge decreases slowly after the irradiation. That puts serious problems of tests validation and of qualification [Wino-94 for example]. Moreover one can separate the apparently permanent part of the effect that exists immediately after the irradiation, and the part that evolves in time through the use of "Post-Irradiation Effects" (PIE) analysis. The speed of neutralization of trapped charge is both a function of the temperature and of the electrical field (applied + space-charge). For example, at room temperature, 50% of charge can be neutralized between 100 and 1000 hours, but the coefficient of neutralization is essentially variable from a manufacturing process to the other, and of the oxide "quality", and of the irradiation duration and dose rate itself. Two mechanisms are generally invoked: The compensation of positive charge by electrons, coming from the silicon, that cross the barrier of the interface by tunneling. The probability of tunneling is independent of temperature (if the tunnel effect is not assisted), and varies exponentially with the distance to interface. Thermal emission of electron from the valence band to traps: the thermal emission varies exponentially with the inverse of temperature but it is independent of the spatial trap distribution