Investigation of Design Space for Ge UTB Negative Capacitance FETs and Fin-LER Induced Variability for Negative Capacitance FinFETs

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In this thesis, we first investigate the design spaces for hetero-channel Ge UTBB NCFET. The results show the channel permittivity difference and the effective built-in back gate bias which is significant for Ge pFET are two primary factors that affect the UTBB NCFET design space. The higher permittivity channel that enhances the vertical field and increases the short channel effects is a superiority for UTBB NCFET design. On the other hand, the forward effective built-in back gate bias may degrade the UTBB NCEFT design spaces for the p-type Ge-channel UTBB NCFET comparing to the n-type Ge-channel counterparts. Besides the device design space, we also investigate the NC-FinFET intrinsic variability. The NC-FinFET exhibits superior immunity toward Fin-LER induced variabilities due to the negative capacitance feedback mechanisms including the amplification effect as well as the relation between short channel effects and the voltage gain. Furthermore, the trap position and number induced variabilities are also suppressed in NC-FinFETs. The suppression results from the negative capacitance feedback mechanism and the negative capacitance reduced effective oxide thickness for NC-FinFETs.