LKE and BGI Lorentzian noise in strained and non-strained tri-gate SOI FinFETs with HfSiON/SiO 2 gate dielectric

Abstract

The LKE (Linear Kink Effect) and BGI (Back-Gate-Induced) Lorentzians present in the drain current noise spectra of fully-depleted tri-gate n- and pFinFETs, fabricated on sSOI and SOI substrates with HfSiON/SiO 2 gate dielectric are described. It is shown that the analysis of the parameters of LKE and BGI Lorentzians allows to find the values of ( С eq / m′ β 2), β and [ j EVB/( m′ β) 2] where С eq is the body-source capacitance, m′ ≈ 1, β is the body factor and j EVB is the density of the EVB current flowing through the gate dielectric. As a result, the following effects were observed for the first time: (i) ( С eq / m′ β 2) decreases with increasing gate overdrive voltage | V ∗ | and depends sub-linearly on the effective fin width W eff under strong inversion conditions; (ii) in depletion and weak inversion where ( С eq / β 2) is independent of | V ∗ | the proportionality ( С eq / β 2) ∝ W eff is observed for an effective width W eff ⩾ 0.87 μm while ( С eq / β 2) becomes independent on W eff for W eff < 0.87 μm; (iii) the value of β for the FinFETs investigated is higher than for their planar counterparts; (iv) in spite of the fact that strain affects the barrier height at the Si/SiO 2 interface, the EVB current densities j EVB for sSOI and SOI devices are equal; (v) the values of j EVB for the HfSiON/SiO 2-devices are much higher than for the HfО 2/SiO 2-ones studied previously. It is also shown that the gate overdrive voltage | V ∗ | at which the LKE Lorentzians start to appear is as low as 0.25 V.