Impact of diameter on TFET conduction mechanisms

In this work, the impact of diameter on the TFET conduction mechanisms and the consequent influence on the device performance is investigated through simulation analysis. The results show a higher current level and a lower gate voltage to reach the band-to-band tunneling regime in NW-TFETs with smaller diameters. Some anomalies related to the performance degradation were found in the transfer characteristic curves of the narrower devices (D <; 30 nm) and are analyzed based on the simulated energy band diagrams and tunneling rate values. The Si NW-TFET with 10 nm diameter presented a drain current approximately 3 orders of magnitude lower than the larger nanowires at high gate voltages due to presence of gate/source overlap region in abrupt source/channel junction.