Source-to-drain Tunneling Analysis in p-type Si and Ge Based NWTs/NSTs

We examine the dependence of source-to-drain tunneling (SDT) leakage on the effective channel length (L
eff
) for Si and Ge pMOS with L
eff
ranging from 5 nm to 20 nm. The subband Boltzmann transport equation is solved including the SDT process, which is evaluated from the WKB approximation. Device architectures including nanosheet transistors (NSTs) and nanowire transistors (NWTs) with the proper specification are analyzed. The results show that SDT becomes a serious concern for Ge pNSTs with L
eff
lower than 17 nm. However, such leakage degradation from SDT, can be further mitigated by optimizing the cross-sectional configuration.