US Patent 7474114 System and method for characterizing silicon wafers

A method and system is provided for characterizing silicon wafers. The method and system provide for measuring a resistance between a pair of points on an epitaxial layer of a wafer's surface. The points may be substantially equidistant from the center of the wafer. The resistance measuring may be repeated at a series of pairs of points, each pair of points being radially spaced apart from an adjacent pair of points. The series of pairs of points may include a control group of pairs. A figure of merit may be calculated by subtracting from 1.0 the ratio of a minimum resistance of the resistances measured between the pairs of points to an average of the resistances measured between the pairs of points in the control.