ERRORS IN RESISTIVITIES CALCULATED BY MULTILAYER ANALYSIS OF SPREADING RESISTANCES

The use of multilayer analysis schemes for calculating resistivity profiles from spreading resistance measurements in semiconductors is well established. All of the techniques make use of the approximation that the current density at a perfectly conducting probe can in all cases be represented by the current density which would exist in a medium of uniform resistivity. We present improved approximate current density profiles for the case of a probe in contact with a single layer over an infinite substrate for a wide range of layer thickness to probe radius ratios and layer resistivity to substrate resistivity ratios. Using these we find the errors incurred using the standard approximation to be limited to 10% when the layer thicknesses become smaller than 10% of the probe radius and less for larger thicknesses. We find-there is a large class of current density profiles for which the situation is no worse, which may be desirable for reasons other than accuracy. © 1979, The Electrochemical Society, Inc. All rights reserved.