Low-frequency noise in advanced CMOS/SOI devices

The low-frequency noise (LFN) in partially- and fully-depleted SOI CMOS technologies is overviewed. The static performances and the drain current noise in both linear and saturation regimes are presented for different SOI architectures. Particular attention is paid to the floating body effect that induces a kink-related excess noise, which superimposes a Lorentzian spectrum on the flicker noise. The behaviour of this effect with the frequency and the physical mechanisms explaining this excess noise, are discussed. The control of this noise overshoot by using a body contact or by applying a back gate voltage is also demonstrated. Also, LFN in DTMOS (dynamic threshold MOS) with the body connected to the gate is studied. The use of a clamping transistor as a body current limiter results in excess Lorentzian-like noise, which is similar to the noise induced by the kink effect. Finally, the influence of the gate leakage in an SOI MOS with thin oxide is shown.