This paper presents a germanium-around-source gate-all-around tunnelling field-effect transistor (GAS GAA TFET). The electrical characteristics of the device were studied and compared with those of silicon gate-all-around and germanium-based-source gate-all-around tunnel field-effect transistors. Furthermore, the electrical characteristics were optimised using Synopsys Sentaurus technology computer-aided design (TCAD). The GAS GAA TFET contains a combination of around-source germanium and silicon, which have different bandgaps. With an increase in the gate-source voltage, band-to-band tunnelling (BTBT) in silicon rapidly approached saturation since germanium has a higher BTBT probability than silicon. At this moment, germanium could still supply current increment, resulting in a steady and steep average subthreshold swing (SSAVG) and a higher ON-state current. The GAS GAA TFET was optimised through work function and drain overlapping engineering. The optimised GAS GAA TFET exhibited a high ON-state current (ION) (11.9 μA), a low OFF-state current (IOFF) (2.85 × 10-9 μA), and a low and steady SSAVG (57.29 mV/decade), with the OFF-state current increasing by 107 times. The GAS GAA TFET has high potential for use in low-power applications.
This is an open access article distributed under the Creative Commons Attribution License
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited