On the calculation of the quasi-bound-state energies and lifetimes in inverted MOS structures with ultrathin oxides and its application to the direct tunneling current

We discuss the inverted MOS structure with extremely thin oxides as a quasi-bound-state system. Its energy subbands can be regarded as resonances of a quantum mechanical system with a continuum of eigenstates. We derive an analytical calculation to extract the defining parameters of the Lorentzian peaks associated with the relative probability of localizing an electron in the confining potential region at the Si/dielectric interface and propose an algorithm that allows to estimate the energy levels and the lifetimes of these states, provided the solution of the approximate bound state system is known. This new method has the advantage of not being affected by computational errors, avoiding the time consuming scanning procedure usually employed in previously reported works. Furthermore, a comparison with semiclassical calculation of the lifetimes is performed and direct tunneling current is calculated, which allows it to fit experimental gate-leakage curves with high accuracy.