Theory of quasi-ballistic FET: steady-state regime and low-frequency noise

Abstract We present a theoretical analysis of steady state regimes and low-frequency noise in quasi-ballistic field effect transistors (FETs). The noise analysis is based on the Langevin approach, which accounts for the microscopic sources of fluctuations originating from intrachannel electron scattering. The general formulas for local fluctuations of the carrier concentration, velocity and electrostatic potential, as well as their distributions along the channel, are found as functions of applied voltage/current. Two circuit regimes with stabilized current and stabilized voltage are considered. The noise intensities for devices with different electron ballisticity in the channel are compared. We suggest that the presented analysis allows a better comprehension of the physics of electron transport and fluctuations in quasi-ballistic FETs, improves their theoretical description and can be useful for device simulation and design.