How Does Spreading Resistance Affect Four Point Probe Measurements?

[caedar]

I'm doing four point probe measurements on contacts to semiconductor materials, and I'm trying to understand the effects of each type of resistance observed in probe measurements. Spreading resistance has been pretty elusive - nowhere seems to have a good definition of what it is except that it has to do with the distribution of dopant atoms. Any help explaining? Thanks!

 

[jsgruszynski]

http://en.wikipedia.org/wiki/Spreading_Resistance_Profiling