Impact of Process Fluctuations on RF Small-Signal Parameter of Gate-All-Around Nanosheet Transistor Beyond 3 nm Node

摘要

In the present work, the variations of RF small-signal model parameters induced by the intrinsic process fluctuations are investigated in gate-all-around (GAA) nanosheet transistor beyond 3 nm node. With the help of nonlinear rational function fitting, the RF small-signal model parameters are first analytically extracted from the non-quasi-static (NQS) equivalent circuit. The impact of work-function variation (WFV), line edge roughness (LER), and gate edge roughness (GER) on small-signal model parameters are evaluated by 3-D TCAD simulation. Results demonstrate that the channel distribution resistance $R_{gdi}$ and $R_{gsi}$ are the most sensitive parameters to intrinsic process fluctuations. Furthermore, compared to LER and GER, WFV is found to have the dominated role in the variation of RF small-signal parameters, while LER and GER played a positive promotion role in aggravating the variation. The underlying physical mechanisms are discussed in detail.

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