Low frequency noise in MOS transistors—I Theory

Abstract

The low frequency noise voltage spectrum for a MOS transistor is calculated under the assumption that a time constant dispersion, giving a 1/ƒ- spectrum , is caused by tunneling of carriers at the silicon-silicon oxide interface to traps located inside the oxide. The magnitude of the noise from different trap distributions is calculated. The largest noise contribution is shown to come from traps near the quasi Fermi level of the current carriers in the channel. The influence of temperature and operating point on the noise is examined. The theoretically predicted noise magnitude agrees with the experimental results (presented in Part II). The theory presented describes qualitatively the shape of the low frequency noise spectrum.