Advantage of NW structure in preservation of SRB-induced strain and investigation of off-state leakage in strained stacked Ge NW pFET

Nanowires (NW) and nanosheets (NS) are promising channel structure for future technology nodes as they can offer better electrostatics than FinFETs. In this paper, we show another advantage of strained Ge NW pFET over strained Ge FinFET, which lies in the preservation of Strain-Relaxed-Buffer (SRB)-induced strain through fin cut and S/D recess. This benefit comes from the presence of the sacrificial SiGe layers. Lowering the Ge concentration in the SiGe sacrificial layer is a way to further suppress the strain loss. Furthermore, a comparison of Ge NW pFETs integrated on Ge SRB and SiGe SRB reveals that SiGe SRB provides a huge advantage not only in the strain engineering but also in I_OFF control. These are key enablers in maximizing the performance while minimizing the I_OFF of strained Ge NW pFETs.