COMPARISON OF DIFFERENT ANALYTICAL TECHNIQUES IN MEASURING THE SURFACE REGION OF ULTRASHALLOW DOPING PROFILES

Accurate knowledge of the dopant surface concentration of ultrashallow junctions is very important, especially since high surface concentrat ions are often encountered and these could have serious consequences o n device performance. Our group has studied several different analytic al techniques to understand the boron surface concentration of plasma- doped p(+)-n junctions that are about 60 nm deep. Secondary ion mass s pectrometry has been performed with both oxygen and cesium primary ion s. The O-2(+) secondary ion mass spectrometry was carried out both in vacuo and with an oxygen bleed to minimize surface ion yield transient s. In addition, the surface boron concentration has been measured by r esonance ionization mass spectrometry and Auger electron spectroscopy. Finally, the surface electrical carrier concentration of these p(+)-n junctions has been determined by spreading resistance profiling, diff erential Hall effect profiling, and microwave surface impedance profil ing. A comparison of the surface results of these various measurement techniques will be presented and discussed in this article. (C) 1996 A merican Vacuum Society.