A comprehensive analytical model of the secondary impact ionization (2II)-induced gate current is developed based on the lucky electron concept. This model takes the substrate bias and the temperature dependence of the mechanism very well into account. In addition, the light emission characteristics of the 2II phenomenon and its correlation with the substrate and gate current is investigated. It is concluded that the 2II-induced photons likely originate from valence intra-band transitions. In view of these results, the worst case aging condition and the impact of the device architecture on hot carrier degradation are also discussed. (C) 2002 Elsevier Science Ltd. All rights reserved.