Impact of Gate Electrodes on Noise of Gate-All-Around Silicon Nanowire Transistors

The low-frequency (1/f) noise of gate-all-around silicon nanowire transistors (SNWTs) with different gate electrodes (poly-Si gate, doped fully silicided (FUSI) gate, and undoped FUSI gate) is studied in the strong-inversion linear region. It shows that the gate electrodes have a strong impact on the 1/f noise of the SNWTs. The highest noise is observed in the SNWTs with a poly-Si gate, compared to their FUSI-gate counterparts. The observations are explained according to the number fluctuation with correlated mobility fluctuation theory by assuming that the correlated mobility scattering is better screened in the case of an undoped FUSI gate. However, the doped FUSI gate with silicidation-induced impurity segregation at the gate/SiO₂ interface gives rise to extra mobility scattering.