Analysis of circular transfer length methods for the optimization of metal contacts on wafers

The aim of this work is to make a comparison between the different TLM and CTLM methods explained in previous papers to extract conclusions about which is the most accurate method to determine the specific contact resistance depending on the sheet resistance of the semiconductor and the quality of the contacts. Measurements of the contact resistance have been simulated according to the equations for the TLM and CTLM methods to determine their sensitivity to input data uncertainties. Experimental measurements of metal/semiconductor contact resistances have been also carried out using Ge samples with different doping levels to compare with the theoretical results, showing a significant discrepancy.