Theory of low-frequency generation noise in junction-gate field-effect transistors

The theory of the low-frequency generation noise from charge fluctuation of the Shockley-Read-Hall centers in the transition regon of the gate junction of a field-effect transistor is presented. The dominant importance of this mechanism in the transition region compared with other mechanisms in the channel (thermal noise and carrier concentration fluctuation) is shown using a simple one-dimensional model at low frequencies. The two-dimensional analysis of this noise mechanism is then worked out in the gradual channel approximation using both the electrostatic field and the lumped circuit model approaches. Nonideal effects such as surface noise and gate-junction transition region noise outside of the channel are discussed and are found to be negligible compared with this mechanism. It is shown explicitly that the previously published noise theory of the junction-gate field-effect transistors neglects the contribution from this noise source.