Investigation of leakage in FinEHBTFET with stack-gate underlaps

In this work, we investigated the parasitic leakage in Fin Electron-Hole Bilayer Tunnel Field-Effect Transistors (Fin EHBTFETs). It has been observed that the gate underlaps and corner-effect in the FinEHBTFETs lead to parasitic OFF state tunneling which degrades the device performance. However, by using a combination of an interfacial low-k SiO₂ layer followed by a high-k HfO2 layer in the underlaps, the OFF state leakage is suppressed by 62.305% in Si FinEHBTFET. Further, improved Si/SiO₂ interface electrostatics lead to an improvement in the ON current by 36.279% improving the Ion/Ioff ratio by four times. On implementing a similar underlap gate stack in Germanium FinEHBTFET, a sharp subthreshold swing of 20.361m V/dec is achieved which is improved by 30.708% compared to that for conventional Ge FinEHBTFET without stack gate underlaps.