A model for the drain voltage and gate voltage dependence of the current fluctuation spectrum of unsaturated JFET´s

From the standpoint of the number fluctuation model of the generation-recombination noise and 1/ noise, a model for the drain and gate voltage dependences of the current fluctuation spectrum of an unsaturated JFET ot MESFET can be established. The derived formula can explain the various experimental results, especially the square-law dependence of the drain voltage throughout almost all of the unsaturated region, and the increasing characteristic of the current fluctuation spectrum with increasing reverse gate voltage. It can also explain the dependence of drain current fluctuation on the device geometric parameters, and finally, it points out that Hooge\´s expression for the spectral intensity of the current fluctuation can be valid only in the linear region of the device.