Current/voltage characteristics, channel pinchoff and field dependence of carrier velocity in silicon insulated-gate field-effect transistors

It is shown that charge carriers moving in the surface channel reach their scattering-limited drift velocity as the current reaches its saturation value. A longitudinal velocity/field relationship is proposed for the surface channel, based on that which exists in the bulk lattice. This leads to simple expressions for current and transconductance which agree satisfactorily with experimental data. Theoretical characteristics are presented to illustrate the effects of field dependence of carrier mobility on operating characteristics.