Germanium-source germanium-channel silicon-drain vertical TFET for low power applications

Scaling problems associated with the MOSFET calls for other novel devices which can outperform MOSFET at nanometer dimensions. As device dimensions shrink, various tunneling leakage factors in the MOSFET increase due to non-scalable junction electric fields. Devices based on tunneling currents can be effectively used as a solution to this problem. In this paper, a novel concept of a particular type of tunnel field effect transistor (TFET) with gate controlled band to band tunneling as its working principle is presented and it is observed that a germanium source-germanium channel-silicon drain TFET is able to provide better on current to off current ratios compared to a silicon TFET thus enabling efficient operation at low supply voltage and power. In this work, the TFET structure is studied and design parameters are optimized based on theory and simulation results to have high on current to off current ratio. Synopsis® device simulation tool MEDICI® is used for the simulations.