Effect of asymmetrical double-pockets and gate-drain underlap on Schottky barrier tunneling FET: Ambipolar conduction vs. high frequency performance

• A proposed asymmetrical double pockets SB-TFET with gate-drain underlap is presented.
• The structure provides a suppression of ambipolarity and a high performance of high frequency characteristics.
• An optimum choice was found which gives minimum ambipolar conduction and maximum cut-off frequency.

In this paper, a proposed structure based on asymmetrical double pockets SB-TFET with gate-drain underlap is presented. 2D extensive modeling and simulation, using Silvaco TCAD, were carried out to study the effect of both underlap length and pockets’ doping on the transistor performance. It was found that the underlap from the drain side suppresses the ambipolar conduction and doesn’t enhance the high-frequency characteristics. The enhancement of the high-frequency characteristics could be realized by increasing the doping of the drain pocket over the doping of the source pocket. An optimum choice was found which gives the conditions of minimum ambipolar conduction, maximum ON current and maximum cut-off frequency. These enhancements render the device more competitive as a nanometer transistor.