Hot electrons in MOS transistors: Lateral distribution of the trapped oxide charge

The spatial distribution (along the channel) of the oxide-trapped charge induced by hot electron injection in MOS transistors biased in saturation, is studied by means of two-dimensional device simulators. It is shown that hot electron trapping leads to a charge almost uniformly distributed over the region included between the points of channel pinch-off and zero transversal component of the surface electric field. A simplified analytic expression for the drain current in the triode operating region of the HE modified transistor is also given and found to be in reasonable agreement with experimental curves.