Patent ID: 7852093
Filing Date: 2010-12-14
Classification: G01R

Abstract:
1. A method for calculating a correction factor for reduction of positional errors in resistance measurements using a four-point probe, said four-point probe having a body and four probe arms each including a probe, said probe arms extending parallel from said body, said four-point probe including electrical contact points for establishing electrical contact between said probes of said probe arms and a test apparatus operable for transmitting and receiving electrical signals, said method comprising said steps of: (a) positioning said probe arms in contact with a surface of a test sample, (b) selecting a first set comprising a first and a second probe arm and a second set comprising a third and a fourth probe arm, (c) applying a first current from said test apparatus through said first probe arm of said first set to said second probe arm of said first set, said first current propagating through said test sample, (d) detecting a first induced voltage between said third and fourth probe arms of said second set, (e) calculating a first four-point resistance, R (f) selecting a third set comprising a first and a second probe arm, wherein said third set includes no more than one of said probe arms of said first set, and a fourth set comprising a third and a fourth probe arm wherein said fourth set includes no more than one of said probe arms of said second set, (g) applying a second current from said test apparatus through said first probe arm of said third set to said second probe arm of said third set, said second current propagating through said test sample, (h) detecting a second induced voltage at said third and fourth probe arms of said fourth set, (i) calculating a second four-point resistance, R (j) calculating a correction factor based on said first and second four-point resistances.