A STUDY OF FLICKER NOISE IN MOS-TRANSISTORS OPERATED AT ROOM AND LIQUID-HELIUM TEMPERATURES

A study of the flicker noise in MOS transistors operated in the linear and non linear regions at room and liquid helium temperatures is proposed. Besides, a theoretical analysis of the drain current noise characteristics is developed in the framework of the mobility fluctuation model as well as of the carrier number fluctuation model. It is shown experimentally that a close correlation between the drain current spectral density and the transconductance squared dependencies with gate voltage (or drain current) and drain voltage is observed in our devices both at room and liquid helium temperatures. Therefore, it is concluded that the carrier number fluctuation model is not only applicable to MOS devices operated at room temperature but also at liquid helium temperature in ohmic and non ohmic regimes. In addition, peculiarities of the drain current noise related to the appearance of a kink effect at liquid helium temperature in the saturation current characteristics are also discussed.