The impact of intrinsic series resistance on MOSFET scaling.
01 January 1987
The intrinsic parasitic series resistance associated with the practical structure of a MOSFET is examined. The components considered include contact resistance, diffusion sheet resistance, spreading(injection) resistance and accumulation layer resistance. The impact of the total resistance on MOSFET scaling is assessed, down to a channel length of 0.15micron. The results show that, contrary to what has been claimed before, the transconductance and current of a MOSFET continue to increase as the channel length is miniaturized, although the degradation percentage- wise compared to an ideal device without series resistance continues to increase. Based on the degraded I-V characteristics and their effects on an inverter, it is shown here that for NMOS or PMOS digital circuits, the maximum degradation in speed is 20-35% for the shortest channel considered. For CMOS circuits, the maximum degradation is reduced to 12-27%.