Vertically-stacked Si0.2Ge0.8 Nanosheet Tunnel FET with 70 mV/dec Average Subthreshold Swing

A novel CMOS-compatible SiGe Tunnel Field-Effect Transistor (TFET) with a high current drivability is demonstrated, which features a vertically-stacked SiGe nanosheet (NS) with high Ge content and gate-all-around(GAA) structure to improve carrier injection efficiency and gate controllability. A multi-NS Si 0.2 Ge0.8 channel is formed by the Si selective etching and Ge condensation technique. The measured data shows both the 50 mV/dec minimum subthreshold swing (SS) and 70 mV/dec average SS over 3 decades of drain current change. Compared to previously reported devices, it is clear that the proposed SiGe nanosheet TFET can achieve steeper switching and low-level leakage current with a low drive voltage as an alternative to conventional MOSFET.