ABSTRACTThe degradation and breakdown of thin silicon dioxide films has been analysed using a two-step stress method. This procedure allows the evaluation of the degradation induced by the electrical stress without any assumption about the microscopic nature of the degradation process. The method has been used to analyse and compare the degradation dynamics when constant-voltage (CVS) and constant-current stresses (CCS) are applied to the oxide. Moreover, it is shown that in the case of CVS, the fitting of the I-t characteristics can provide quantitative information about the degradation (degradation rate) and breakdown (mean-time-to-breakdown), without taking into account any degradation model.