Abstract-The reduction of the critical dimensions of transistor architectures makes mandatory the inclusion of quantum effects different than standard confinement becomes in advanced device simulators to describe the electrical behavior. In particular, direct tunneling from source to drain, band-to-band tunneling and gate leakage mechanisms considering direct and trap assisted tunneling are of especial interest. This work presents a study of these mechanisms in Fully Depleted Silicon-OnInsulator (FDSOI) and FinFET devices using a Multi-Subband Ensemble Monte Carlo (MS-EMC) simulator.