Anomalous kink-related excess noise in MOSFETs at 4.2 K

The anomalous drain-voltage-dependent excess noise that is observed in silicon MOSFETs at cryogenic temperatures is examined. A model for the underlying physics is described. It is shown that the mechanisms inducing this excess noise are shallow-level impact ionization and trapping in the bulk of the MOSFET. A model for the noise spectrum and amplitude is proposed and is validated by the measurements. Evidence-both theoretical and experimental-is presented for the correlation between the anomalous low-frequency noise and the kink/hysteresis observed in the characteristics of MOSFETs operating at 4.2 K.<
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