A study of cross-bridge kelvin resistor structures for reliable measurement of low contact resistances

The parasitic factors that strongly influence the measurement accuracy of cross-bridge Kelvin Resistor (CBKR) structures for low specific contact resistances (p
_c
) have been extensively discussed during last few decades and the minimum of the p
_c
value, which could be accurately extracted, was estimated. We fabricated a set of various metal-to-metal CBKR structures with different geometries, i.e., shapes and dimensions, to confirm this limit experimentally. As a result, a model was developed to account for the actual current flow and a method for reliable p
_c
extraction was created. It was found that in our case of metal-to- metal contacts, the measured CBKR contact resistance was determined by the dimensions of the two-metal stack in the area of contact and sheet resistances of the metals used.