Investigation of Low-Frequency Noise in N-Channel FinFETs From Weak to Strong Inversion

Low-frequency noise in 4H-SiC MOSFETs has been measured for the first time. At drain currents varying from deep subthreshold to strong inversion, the 1/f (flicker) noise dominated at frequencies 1 - 105 Hz. The dependence of relative spectral noise density, , on drain current Id (at a constant drain voltage Vd) differs qualitatively from that in Si MOSFETs. In Si MOSFETs, ~ 1/ in strong inversion, whereas tends to saturate in sub-threshold. In 4H-SiC MOSFETs under study, ~ 1/ over the whole range of currents from deep sub-threshold to strong inversion. Similar noise behavior is often observed in poly- or a-Si TFTs. The effective channel mobility in 4H-SiC MOSFETs, 3 - 7 cm2/Vs, is also as low as that in TFTs. Both noise behavior and transport properties of 4H-SiC MOSFETs are explained, analogously to TFTs, by a high density of localized states (bulk and interface) near the conduction band edge in the ion implanted p-well.

Download Full-text

ON THE ORIGIN OF 1/F NOISE IN MOSFETS

Fluctuation and Noise Letters ◽

10.1142/s0219477507003970 ◽

2007 ◽

Vol 07 (03) ◽

pp. L321-L339 ◽

Cited By ~ 5

Author(s):

L. K. J. VANDAMME

Keyword(s):

Empirical Relation ◽

Low Frequency ◽

Frequency Noise ◽

Low Frequency Noise ◽

Time Constants ◽

Strong Inversion ◽

Typical Shape ◽

Rts Noise ◽

Lorentzian Spectrum ◽

Mobility Fluctuations

Often the 1/f noise in MOSFETs is stated to be an ensemble of many RTS with different time constants. The majority of literature on 1/f noise is overlooking the contribution due to mobility fluctuations that are uncorrelated with number fluctuations. Here, we demonstrate that the so-called proofs for Δ N can also be obtained from the empirical relation. The following misunderstandings and controversial topics on the surface and bulk contributions to the low-frequency noise will be addressed: 1) 1/f and RTS noise can have different physical origins. An analysis in time domain shows that the low-frequency noise with RTS is nothing else than a superposition of a two level noise with a Lorentzian spectrum and a Gaussian noise with a pure 1/f spectrum and different bias dependency. 2) It is very unlikely that in a spectrum consisting of one strong two level RTS and a pure 1/f noise, the 1/f noise is a superposition of many RTS with different time constants. 3) The spreading in WLS I /I2 below a critical WL is not a proof for the Δ N origin. 4) The typical shape in the double log plot from sub threshold to strong inversion of S I/ I 2 versus I , is also not a proof for the Δ N origin.

Download Full-text

Semianalytical Modelling and 2D Numerical Simulation of Low-Frequency Noise in Advanced N-Channel FDSOI MOSFETs

Active and Passive Electronic Components ◽

10.1155/2020/7989238 ◽

2020 ◽

Vol 2020 ◽

pp. 1-10

Author(s):

T. Boutchacha ◽

G. Ghibaudo

Keyword(s):

Noise Level ◽

Low Frequency ◽

Silicon On Insulator ◽

Excess Noise ◽

Channel Noise ◽

Flat Band ◽

Frequency Noise ◽

Low Frequency Noise ◽

Noise Sources ◽

Strong Inversion

Thorough investigations of the low-frequency noise (LFN) in a fully depleted silicon-on-insulator technology node have been accomplished, pointing out on the contribution of the buried oxide (BOX) and the Si-BOX interface to the total drain current noise level. A new analytical multilayer gate stack flat-band voltage fluctuation-based model has been established, and 2D numerical simulations have been carried out to identify the main noise sources and related parameters on which the LFN depends. The increase of the noise at strong inversion could be explained by the access resistance contribution to the 1/f noise. Therefore, considering uncorrelated noise sources in the channel and in the source/drain regions, the total low-frequency noise can simply be obtained by adding to the channel noise the contribution of the excess noise originating from the access region (Δr). Moreover, only two fit parameters are used in this work: the trap volumetric density in the BOX, and the 1/f access noise level originating from the access series resistance, which is assumed to be the same for the front and the back interfaces.

Download Full-text