Non-iterative NEGF based model for band-to-band tunneling current in DG TFETs

Since the last few years, Tunnel-FETs (TFET) have moved into the center of focus. The device has the physical property to go below the milestone of 60mV/dec slope, which cannot be achieved by standard MOSFETs. In the meantime, there exists a great diversity of TFETs. In order to accurately model this TFET variety, not only a precise potential calculation is sufficient. A similar precision is needed to calculated the tunneling current. There exist some methods to calculate the tunneling current in TFETs such as the Wentzel-Kramers-Brillouin (WKB) and Kane's equation. Since the tunneling current is a quantum mechanical effect, the Non-Equilibrium Green's Function (NEGF) is also able to accurately calculate this type of current. This work presents a combination of an accurate potential calculation for TFETs with an 1D compact non-iterative NEGF based current calculation method. Since the applied NEGF deals just with one conduction band and does not consider the valence band, mathematical approximations are introduced to map these two bands into an equivalent description by only one conduction band. The results show an accurate current behavior in the on- and off-state of the device.