A new technique involving harmonic generation in measuring the doping profile normal to the surface of semiconductor epitaxial wafers has been developed. This method has been used in the construction of a direct-plotting inverse-doping profiler which can determine the doping concentration with an absolute accuracy of about 10 percent and a relative accuracy of a few per-cent. The depth resolution is on the order of a Debye length. The profiler has the advantages of providing immediate results and accuracy at low cost. Copyright © 1969 by The Institute of Electrical and Electronics Engineers, Inc.