Physical model of noise mechanisms in SOI and bulk-silicon MOSFETs for RF applications

Alberto O. Adan, Mitsumasa Koyanagi, Masayuki Fukumi

Research output: Contribution to journalArticlepeer-review

17 Citations (Scopus)


The noise mechanisms at high frequencies in MOSFETs are analyzed and an analytical model is presented for devices operating at gigahertz frequencies. The proposed model is applied to floating body silicon-on-insulator (SOI) as well as bulk-silicon MOS transistors and experimentally verified. The model accounts for the mechanisms of 1) channel thermal noise; 2) shot-noise due to impact ionization; and 3) substrate back-gate-coupled thermal noise. Compact, closed-form analytical expressions of the noise power spectral density and the minimum noise figure (NF) are presented. At the same technology level, the experimental data and the model show that SOI MOSFETs are able to attain lower NF than bulk-silicon devices by reduction of the back-gate transconductance. However, the higher drain electric field in the SOI, and the parasitic bipolar action and floating body enhance impact-ionization-associated shot-noise, which becomes the limiting noise mechanism at drain voltages Vds higher than the drain onset voltage Vdk of "kink" effect. A correlation between the onset voltage Vdk and the dc electrical characteristics is shown.

Original languageEnglish
Pages (from-to)872-880
Number of pages9
JournalIEEE Transactions on Electron Devices
Issue number3
Publication statusPublished - 2008 Mar
Externally publishedYes


  • CMOS
  • Noise
  • RF
  • SOI

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering


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