Complementary Germanium Electron-Hole Bilayer Tunnel FET for Sub-0.5-V Operation

In this paper we present a novel device, the Germanium Electron-Hole Bilayer Tunnel FET (Ge EHBTFET), which exploits carrier tunneling through a bias-induced electron-hole bilayer. The proposed architecture provides a quasi-ideal alignment between the tunneling path and the electric field controlled by the gate. The device principle and performances are studied by 2D numerical simulations. This device allows interesting features in terms of low operating voltage (< 0.5 V), due to its super-steep subthreshold slope (SSavg ~ 13 mV/dec over 6 decades of current), Ion/Ioff ratio of 10^9, and drive current Ion ~ 10 uA/um at Vdd = 0.5 V. The same structure with symmetric voltages can be used to achieve a p-type device with Ion and Ioff levels comparable to the n-type, which enables a straightforward implementation of complementary logic that could theoretically reach a maximum operating frequency of 1.39 GHz when Vdd = 0.25 V.