On the Spreading Resistance of Thin-Film Contacts

The spreading resistance of a microscopic area of contact (the “-spot”) located in a thin film is studied for both Cartesian and cylindrical geometries. The effect of film thickness on the spreading resistance is evaluated over a large range of aspect ratios. In the limit , the normalized thin-film spreading resistance converges to the finite values, i.e., 2.77 for the Cartesian case and 0.28 for the cylindrical case. An interpretation of these limits is given. Extension to a general α-spot geometry is proposed.