Extraction of metallurgical effective channel length in LDD MOSFET´s

A new extraction method of metallurgical effective channel length (L_met) in LDD MOSFET\´s is proposed. This method is based on the clear device physics. First, the carrier density modulation effect is overcome by "paired V_TH" method. Second, the effect of charge sharing is eliminated by extrapolating L_eff found by "paired V_TH" method to that at zero depletion width between the lightly doped region and the substrate. Both simulation and experimental results demonstrate the accuracy and usefulness of our approach. For example, the device simulation result shows that the extracted L_met has only 60 Å error compared with the physical dimension defined by the distance between the source and drain n^- metallurgical junctions. Proposed method is accurate, reliable enough to be used for the routine monitoring in manufacturing environment.