1-nm Spatial Resolution in Carrier Profiling of Ultrashallow Junctions by Scanning Spreading Resistance Microscopy

Recently, we reported significantly improved spatial resolution in scanning spreading resistance microscopy (SSRM) by measuring in a vacuum. In this paper, we demonstrate the 1-nm spatial resolution of SSRM in carrier profiling by comparing with the 3-D device simulation. The simulation results show that the accuracy of ultrashallow-junction delineation depends on the effective radius of the probe. The precisely measured junction depth corresponds to an effective probe radius of 0.5 nm. We attribute the high resolution to the elimination of parasitic resistances of the whole measuring circuit. Application to failure analysis of n-type metal-oxide-semiconductor field-effect transistors clarified the impact of halo-carrier profiles on Vth-roll-off characteristics.