Noise in Semiconductor Devices

Noise (a spontaneous fluctuation in current or in voltage) is generated in all semiconductor devices. The intensity of these fluctuations depends on device type, its manufacturing process, and operating conditions. The resulted noise, as a superposition of different noise sources, is defined as an inherent noise. The equivalent noise models (containing all noise sources) are created for a particular device: for example, bipolar transistor (BJT), junction field effect transistor (JFET), or metal oxide semiconductor field effect transistor (MOSFET). The inherent noise of semiconductor devices is considered as an undesired effect and sometimes is referred to a useful signal. It is specially important for input (front-end) stages of electronic systems. However, the inherent noise can also be used for the quality assessment of semiconductor devices. Quite often it has been used as an important factor during the development of the production process of new semiconductor devices. Inherent noise is also used for the classification of semiconductor devices into groups with different quality and reliability. The most important sources of noise are thermal noise, shot noise, generation-recombination noise, 1/f noise (flicker noise), 1/f 2 noise, burst noise or random telegraph signal (RTS) noise, and avalanche noise. Detailed description of noise sources is presented in references [1–6].