Effect of channel resistance on unipolar transistor characteristics

The effect of inseparable resistance present near the input source electrode in field effect transistor is studied experimentally by varying an added external resistance in the source electrodes. Device physics indicates that this resistance behaves like negative feed-back network due to its non-linear character until input and output of the device are isolated completely where channel potential is lower than the source potential and the semiconductor bulk is depleted completely. In such situations, the effect of non-linear channel resistance is minimized and it behaves precisely as a lumped series resistance. It is explained further that the channel resistance affects the potential profiles of the device till input and output are isolated and it is not the only major factor responsible for current saturation in JFET, but device dimensions, channel doping profile and material properties also contribute significantly. Thus, the potential profile in effect controls the device characteristics of the majority carrier semiconductor devices.