This work presents an original approach to model direct tunneling current through high-K dielectrics including SiO2 interfacial oxide from electron inversion layers. Quantum confinement is taken into account by means of an improved triangular well approximation including physically-based analytical corrections of subband energy levels. An efficient way to compute tunnel transmission probability is also proposed, taking into account the reflections on discontinuous dielectrics interfaces. Finally, this model has been successfully validated by comparison to both numerical simulations and experimental results. (C) 2009 American Vacuum Society. [DOI: 10.1116/1.3043539]