From the fact that good silicon JFET’s do not have any flicker noise, it is concluded that flicker noise in semiconductors and semiconductor devices cannot be a true bulk effect. Since JFET’s have no semiconductor‐oxide interface to speak of, whereas all other semiconductor devices do, this points to the semiconductor‐oxide interface as the source of 1/fnoise. This leads to the following model. The carriers are trapped and detrapped by oxide traps, and this gives rise to two distinct noise effects: density fluctuation noise that can be described by the McWhorter model and mobility fluctuation noise that could possibly be described by the Kleinpenning model. The two models might therefore ultimately be unified into a single model, and it would depend on the device under study whether one or the other noise effect would predominate.