The threshold voltage V t variability in the scaled crystal channel and poly-Si channel double-gate fin-type metal-oxide-semiconductor field-effect transistors (FinFETs) with different gate oxide thicknesses T ox has been systematically analyzed. By investigating the T ox dependence of V t variations in crystal channel FinFETs, the gate-stack origin sources, i.e., work function (φm) variation and gate oxide charge (Q ox) variation sources, were successfully separated. It was found that the atomically flat Si-fin sidewall channels fabricated by the orientation-dependent wet etching contribute to the reduction of gate-stack origin V t variations. Moreover, it was experimentally found that the standard V t deviation (σ V t) of poly-Si channel FinFETs is three times higher than that of crystal channel ones, and a good subthreshold slope in the poly-Si channel FinFETs was obtained with gate length L g down to poly-Si grain size.
- Crystal channel
- fin-type metal-oxide-semiconductor field-effect transistor (FinFET)
- gate work function
- poly-Si channel
- threshold voltage (V )