
205Evaluation of Silicon Wafers
6.23 Spreading Resistance and Two-Point Probe Measurement Technique
Spreading resistance proling is a technique used to analyze resistivity versus depth
in semiconductors. The electrically active carrier prole can be measured in the silicon
bulk and in the processed wafer by proper beveling at small angles. This is a destructive
approach, however, and sample preparation is key to obtaining the necessary information.
It is strongly recommended that samples be beveled before probing to avoid native oxide
formations. This method was rst applied by Mazur and Dickey [184] to study the inho-
mogeneous silicon struct ...