Surface vs. bulk noise in SOI four-gate transistors

Low-frequency noise characteristics of four-gate transistors (G/sup 4/-FETs) are presented distinguishing the surface conduction (MOSFET mode) and volume conduction (JFET mode). As the conducting channel moves from the surface to the bulk we observe that: (i) the noise level dramatically decreases; and (ii) the nature of the noise changes. The validity of the existing noise models for different conduction modes is discussed.