In this paper, a germanium-based gate-metal-core vertical nanowire tunnel field effect transistor (VNWTFET) has been designed and optimized using the technology computer-aided design (TCAD) simulation. In the proposed structure, by locating the gate-metal as a core of the nanowire, a more extensive band-to-band tunneling (BTBT) area can be achieved compared with the conventional core-shell VNWTFETs. The channel thickness (Tch), the gate-metal height (Hg), and the channel height (Hch) were considered as the design parameters for the optimization of device performances. The designed gate-metal-core VNWTFET exhibits outstanding performance, with an on-state current (Ion) of 80.9 μA/μm, off-state current (Ioff) of 1.09 × 10-12 A/μm, threshold voltage (Vt) of 0.21 V, and subthreshold swing (SS) of 42.8 mV/dec. Therefore, the proposed device was demonstrated to be a promising logic device for low-power applications.
Keywords: core–shell; germanium; low power; technology computer-aided design (TCAD); tunnel field-effect transistor (TFET); vertical nanowire.