Effects of injection resistance on the performance of very-short-channel MOSFET´s

Injection resistance, the spreading resistance due to current crowding at the source end of an FET channel, can lead to considerable performance reduction in short-channel MOSFET´s. A simple technique for determining the magnitude of this resistance by means of measurements in the linear operation region is described. A simple analytical model which incorporates the effects of both velocity saturation and injection resistance is also developed. The method and model are experimentally verified by determination of the effects of injection resistance on MOSFET´s with channel lengths from 0.2 to 24.6 µm.