Impacts of diameter-dependent annealing on S/D extension random dopant fluctuations in silicon nanowire MOSFETs

In this paper, the impacts of diameter-dependent annealing (DDA) effect on nanowire S/D extension random dopant fluctuations (SDE-RDF) in silicon nanowire MOSFETs (SNWTs) are investigated, in terms of electrostatic properties, source/drain series resistance (R_SD), and driving current. The SDE-RDF induced variations of threshold voltage (V_th) and DIBL in SNWTs with different diameters are found to be modest and decrease as the diameters down-scale. However, SDE-RDF induced R_SD variation in SNWTs is enhanced by abnormal DDA effects, which aggravates the drive current variations with the downscaling of SNWT diameter. The results also show that V_th is the dominant factor in ON/OFF current ratio variation while R_SD dominates that of ON current. The tradeoff between R_SD and V_th dominant current variations is discussed to give some guidelines for SDE-RDF-aware design in SNWTs.