Highly Biased Linear Condition Method for Separately Extracting Source and Drain Resistance in MOSFETs

A highly biased linear current method (HBLCM) for separately extracting source and drain resistance (R-S and R-D ) in MOSFETs is proposed. The technique can be applied to a single device by using simple modeling. Compared to other methods, it provides accurate values of R-S and R-D because it considers carrier mobility degradation. The method basically uses linear current versus gate voltage (I-DS - V-GS and I-SD - V-GD) characteristics before and after the source/drain interchange (I-DS and I-SD). Afterward, by using the traditional Y-function and subsequent resistance modeling in a highly biased linear condition, R-S and R-D can be separately extracted. In order to evaluate and verify the accuracy of HBLCM, an external resistor was intentionally connected to a source electrode of a device, and the resulting change in source resistance was detected using the proposed method. Moreover, to demonstrate an application of the proposed method, internal resistance deliberately created by hot-carrier injection (HCI) was linked to a drain electrode, thereby changing drain resistance. The changed drain resistance was also sensed by the HBLCM. Aft, the HCI-stressed device was cured by electrothermal annealing driven by Joule heating, and the recovery was again clearly observed using the proposed method.