Flicker noise in metal‐oxide‐semiconductor transistors from liquid helium to room temperature

A study of the normalized drain current spectral density SId/I2d as a function of drain current has been carried out on n channel metal‐oxide‐semiconductor transistors at very low (4 K), low (77 K), and room temperatures. It is demonstrated experimentally that the drain current dependence of SId/I2d is strongly correlated to that of the transconductance‐current ratio squared (gm/Id)2. This result clearly shows that the carrier‐number fluctuation model is applicable not only at room temperature but also at low and very low temperatures. Therefore, it is proved that the mobility fluctuation model is inadequate for the interpretation of our flicker noise data.