$1/f$ Electrical Noise in Planar Resistors: The Joint Effect of a Backgating Noise and an Instrumental Disturbance

Any planar resistor (channel) close to a conducting layer left floating (gate) forms a capacitor C whose thermal voltage noise (kT/C noise) has a backgating effect on the sheet resistance of the channel that is a powerful source of 1/f resistance noise in planar resistors and, hence, in planar devices. This 1/f spectrum is created by the bias voltage V _DS applied to the resistor, which is a disturbance that takes it out of thermal equilibrium and changes the resistance noise that existed in the unbiased device. This theory, which gives the first electrical explanation for 1/f electrical noise, not only gives a theoretical basis for the Hooge´s formula but also allows the design of proper shields to reduce 1/f noise.