Measurement of MOSFET substrate dopant profile via inversion layer-to-substrate capacitance

In this paper, a new method for extracting substrate dopant concentration profile of short-channel MOSFET's is presented. It is based on the measurement of the small-signal capacitance between the inversion layer and the substrate. The method achieves effective deep depletion through dc reverse bias on the inversion-to substrate junction and thus avoids the problems with transients associated with pulsed C-V of MOS capacitors. By using transistors of different drawn lengths the effect of lateral extension of drain and source junction depletion regions is also accounted for.