Novel Linear Graded Binary Metal Alloy PαQ1-α Gate Electrode and Middle N+ Pocket Si0.5Ge0.5 Vertical TFET for High Performance

Abstract

This paper proposes a novel linear graded binary metal alloy PαQ1-α gate electrode and middle N+ pocket of Si0.5Ge0.5 Vertical-TFET (LGN-VTFET) device structure. The device is gradually developed by considering initially the impact of middle N+ pocket of low band Si0.5Ge0.5 material at the channel side and then utilizing the linear graded electrodes work function of binary metal alloy instead of single metal work function. The designed device exhibits fascinating performance enhancement, as it shows 2 orders ON-current improvement over the single work function VTFET (SG-VTFET) keeping the same OFF-current and also, it renders 7 mV/Dec Sub-threshold Slope (SS), which is 79% lower than (SG-VTFET). Inclusion of N+ pocket of Si0.5Ge0.5 causes narrower tunneling band space and hence results in a high tunneling rate. Implementation of the linear graded work function of binary metal alloys causes abrupt decay in the tunneling rate unlike the gradual decay tunneling rate of single work function from the source channel interface towards the channel and in turns, offers steep sub-threshold Slope (SS). This device with a lower SS improves the transistor’s switching and encourages its applicability in high-speed circuits.