August_EDFA_Digital

edfas.org ELECTRONIC DEV ICE FA I LURE ANALYSIS | VOLUME 24 NO . 3 30 SSRM FOR THE FEOL AND BEOL The same multidimensional approach is used in the SSRM mode (Fig. 6a), where the local resistance is de- duced fromthe collected current when a V DC is applied. For SSRM, a high force of 12 µN is applied to the cantilever to assure the presence of the highly conducting metastable Si β-tin phase, [4,5] in the highly stressed region just below the conductive AFM tip (Fig. 6b). Thereby, with this force, the spreading resistance contribution, related to the doping level, dominates the measured total resistance when the tip scans the semiconductor. In this case, the hold segment is fixed to 300 ms, longer than for the SCM measurements, to assure a stable tip-sample contact. The Fig. 7 Flowchart for a comprehensive AFMelectrical analysis; SCMand SSRMacquisitions extracted fromthemultidimensional approach. Fig. 6 SSRM results: (a) schematic of the probe-sample system in the SSRM multidimensional approach; (b) AFM force-curve as a function of time, in this case a large deflection setpoint (force) is applied; (c) evolution of the recorded resistance as a function of the applied voltage; and (d) SSRM-DCUBE slices extracted for various V DC values from – 3V to 3 V. (a) (b) (c) (d) ELECTRICAL CHARACTERIZATIONS BASED ON AFM (continued from page 27)