A 2D closed form model for the electrostatics in hetero-junction double-gate tunnel-FETs for calculation of band-to-band tunneling current

In the last few years the Tunnel-FET has become one of the promising devices to be the successor of the MOSFET due to its CMOS compatibility and steep subthreshold slopes (S) below 60 mV/dec. Hetero-junctions at the channel interface are used to improve the on-state current of the device. In this paper a 2D physics-based analytical model for hetero-junction Tunnel-FETs is introduced. It predicts a 2D band-to-band tunneling probability calculation through Wentzel–Kramers–Brillouin approximation (WKB) based on a 2D solution of electrostatics with respect to the device structure and carrier distributions in the device. These results are embedded in a model for the device current. The solutions of the potential, electrical field and the current transfer characteristics of the model are in good agreement with simulation data from the finite-element-method (FEM) simulator TCAD Sentaurus.