Open source 4point probe literature review
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SummaryEdit
This review is in support of a project to develop a more costeffective, opensource 4point probe for use in the PV research community. This literature review supported the design of OpenSource Automated Mapping FourPoint Probe, which was published as:
 Handy Chandra, Spencer W. Allen, Shane W. Oberloier, Nupur Bihari, Jephias Gwamuri and Joshua M. Pearce. OpenSource Automated Mapping FourPoint Probe. Materials 2017, 10(2), 110. doi: 10.3390/ma10020110 open access

searchesEdit
Google Scholar
 4 Point Probe
 four point probe measurement
 Solar Panel Parameter Extraction
 four point probe
ASTM International (Link)
 four point probe
Compendex (Engineering Village)
 Four Point Probe
IEEE Xplore
 Four Point Probe
A great overview of 4terminal (kelvin) sensing can be found here.
Solar Panel CharacterizationEdit
A simple and efficient solar cell parameter extraction method from a single currentvoltage curveEdit
Chunfu Zhang, Jincheng Zhang, Yue Hao, Zhenhua Lin, Chunxiang Zue, "A simple and efficient solar cell parameter extraction method from a single currentvoltage curve," Journal of Applied Physics, 110(6), 06504, 2011.
 solar panel electrical characteristics can be modeled with several different models of varying complexity/accuracy
 Singlediode is simplest
 parameters of models are extracted from IV tests of the panels at varying illumination levels
 tests can be wrong since illumination can alter properties
 this paper attempts to simplify tests by solving for the panel parameters as a function of only one test with one illumination level.
 results show acceptable amounts of error for the new functions
Evaluation of crystalline silicon solar cells by currentmodulating fourpointprobe methodEdit
Wugen Pan, Kozo Fujiwara, Satoshi Uda, "Evaluation of crystalline silicon solar cells by currentmodulating fourpointprobe method," Applied Physics Letters, 103(4), 043903, 2013.
 focuses on use of a 4PP specifically for solar panel characterization
 discusses characterization needs for different solar cell types
 characterizes silicon PV cells by measuring resistivity as a function of 4PP current
 an analysis of curve yields a value that can be positively correlated to conversion efficiency
 This analysis method aggregates several parameters that were previously evaluated one at a time
 the importance of this is that it can identify cells with poor performance in an individual tests, but still good performance overall
Four Point Probe (4PP) operation and useEdit
Resistivity Measurements on Germanium for TransistorsEdit
L. B. Valdes, "Resistivity Measurements on Germanium for Transistors," Proceedings of the IRE, 42(2), 420427, 1954.
 Describes the base technique to using a 4PP for measuring the surface resistivity of a semiconductor sample
 Conventional inline four point probe
 Germanium is used as an example, but the article states other semiconductors are equivalent
 requirements and guidelines for accurate measurements are listed
 Measurement cases are listed
 For a semiinfinite sample: p=(V/I)2(pi)s
 measurement near a boundary: p=p0*F_2(l/s)
 p0 is from semiinfinite sample
 a relationship is given for F_2(l/s)
 other boundary cases are presented, all a variation of equation above
 parallel to nonconducting boundary
 " conducting boundary
 conductivity of a thin sample with a conducting base
 " with a nonconducting base
 The pioneer who came up with idea of four point probe to measure resistivity of materials
 Contact Resistance as a problem with conventional methods
The Potentials of Infinite Systems of Sources and Numerical Solutions of Problems in Semiconductor EngineeringEdit
Arthur Uhlir, "The Potentials of Infinite Systems of Sources and Numerical Solutions of Problems in Semiconductor Engineering," Bell System Technical Journal, 34(1), 105128, 1955.
 Decribes a lot of math involving the voltage differential due to a plane of semiinfinite point sources
 gives correction factors for resistivity measurements on semiconductor samples of various geometries
 use of 4PP on thin slices is generally satisfactory
 can be innacurate if one side has a conductive coating, corrections provided
 goes over work by Valdes for calculating resistivity of samples
 some calculations are included for square pattern 4PP
 some calculations for 2PP are included
 calculations are given for measuring resistivity of filaments
Measurement of sheet resistivities with the fourpoint probeEdit
F. M. Smits, "Measurement of sheet resistivities with the fourpoint probe," Bell System Technical Journal, 37(3), 711718, 1958.
 Four point probe as a convenient tool for measuring resistivities
 Inline four point probe with two outer current probe and two inner voltage probe
 describes a formula for calculating sheet resistance based on 4PP measurements
 ps=C(V/I)
 C is a correctional factor that depends on the geometry of the sample and the distance b/n probes
 tables of C's are provided
 describes how to calculate body resistivity of a sample
 p=(V/I)w(pi/ln2)F(w/s)
 A table is given to find F(w/s)
 p=(V/I)w(pi/ln2)F(w/s)
 Basically two correction factors are mentioned, C for finite 2D samples and F(w/s) for finite thickness samples
 Only probes centered on the sample is considered !
Measurement of the Sheet Resistivity of a Square Wafer with a Square Four‐Point ProbeEdit
Frank Keywell, George Dorosheski, "Measurement of the Sheet Resistivity of a Square Wafer with a Square Four‐Point Probe," Review of Scientific Instruments, 31(8), 833837, 1960.
 provides correction factor calculations for a square probe on a square sample
 uses the infinite sheet of dipoles method
Fourprobe resistivity measurements on small circular specimensEdit
D. E. Vaughan, “Fourprobe resistivity measurements on small circular specimens,” Br. J. Appl. Phys., vol. 12, no. 8, p. 414, 1961.
 Focuses on small circular two dimensional material. It is more accurate to use square rather than linear probe configuration on small samples
 Another Correction Factor derivation for using square and linear four point probe array on thin circular material. These correction factor took into account displacement of the center of probe from the geometrical center of the sample
Correction factor curves for squarearray and rectangulararray fourpoint probes near conducting or nonconducting boundariesEdit
S. B. Catalano, "Correction factor curves for squarearray and rectangulararray fourpoint probes near conducting or nonconducting boundaries," IEEE Transactions on Electron Devices, 10(3), 185188, 1963.
 buildes upon work by Valdes for inline 4PP measurement correction factors
 Square and rectangular array 4PPs are analyzed
 Graphs of correction factors are given for various configurations of probes near boundaries
Fourpoint probe measurement of nonuniformities in semiconductor sheet resistivityEdit
L. J. Swartzendruber, "Fourpoint probe measurement of nonuniformities in semiconductor sheet resistivity," SolidState Electronics, 7(6), 413422, 1964.
 Using 4PP to assess uniformity of materials is possible if the nonuniformity radius is larger than the probe spacing. The larger the radius, the more accurate the nonuniformity measurement.
 It is possible to determine nonuniformity radius to within one probe spacing if radius is greater than 1.5 probe spacing.
 Also discuss correction factors for circular sample if probe is not at the center of sample. Only considers case where probe is displaced along the radius of the sample or perpendicular to the radius.
 4PP measurement technique produce an average resistivity within the vicinity of the measurement
 4PP are good at measuring nonuniform resistivities with an effective radius above one and a half the probe spacing
 4PP is more sensitive when the nonuniformity is centered on the voltage probe, and less when it's centered on the current probe
 square array 4PP are always less sensitive to resistivity fluctuations than equaly spaced inline arrays
 nonuniformity sizes can be easily determined by recording reistivity changes across the nonuniformity
 correction factors for measuring circular samples are given
Empirical method of calibrating a 4point microarray for measuring thinfilmsheet resistanceEdit
R. Rymazewski, "Empirical method of calibrating a 4point microarray for measuring thinfilmsheet resistance," Electronics Letters, 3(2), 5758, 1967.
 A way of measuring sheet resistance without calculating correction factor  using dual configuration probe
 Using van der Pauw formula, correction factor can be calculated from the result of dual configuration measurement.
Sheet resistivity measurements on rectangular surfaces–general solution for four point probe conversion factorsEdit
M. A. Logan, "Sheet resistivity measurements on rectangular surfacesgeneral solution for four point probe conversion factors," Bell System Technical Journal, The, 46(10), 22772322, 1967.
 Discussed how to derive correction factors for probe located at any point on the surface of sample.
Relationship between the correction factor of the fourpoint probe value and the selection of potential and current electrodesEdit
R. Rymaszewski, "Relationship between the correction factor of the fourpoint probe value and the selection of potential and current electrodes," Journal of Physics E: Scientific Instruments, 2(2), 170, 1969.
 may not be relevant
 much of the article was spent discussing effects of sample geometries on a square configuration 4PP
 it did reference an additional article that relates to inline 4PPs
 investigates all combinations of four point probe configurations and correction factors for each of them
 Conclude that there are at most three different correction factors regardless the current and voltage probe configuration
Four‐Point Probe Correction Factors for Use in Measuring Large Diameter Doped Semiconductor WafersEdit
David S. Perloff, "Four‐Point Probe Correction Factors for Use in Measuring Large Diameter Doped Semiconductor Wafers," Journal of The Electrochemical Society, 123(11), 17451750, 1976.
 Four point probe as a tool for determining homogeneity of doped semiconductor wafers
 Mentioned reversing current to eliminate small offset voltages associated with thermoelectric effects
 when probe separation is small compared to the radius of a circular sample, correction factors are easier to calculate
 equations are given
 the measurements are orientation independent for this case
 used automat4ed tester for large samples
 the device used is extremely dated
Geometrical Correction Factor for Semiconductor Resistivity Measurements by FourPoint Probe MethodEdit
Masato Yamashita, Masahiro Agu, "Geometrical Correction Factor for Semiconductor Resistivity Measurements by FourPoint Probe Method," Japanese Journal of Applied Physics, 23(111), 14991504, 1984.
 designed for rectangular specimens
 uses conformal transformation and poisson's method to determin correction factors
 Gives correction factors as a function of sample size and thickness
 Math is over me, but his results may be useful
Microfourpoint probe for studying electronic transport through surface statesEdit
C. L. Petersen, F. Grey, I Shiraki, S. Hasegawa, "Microfourpoint probe for studying electronic transport through surface states," Applied Physics Letters, 77(23), 37823784, 2000.
 Using four point probe to study surface state conductivity. Probe spacings in the milimeters range is not suited for this purpose
 4PP spacings between 8 and 20um were used
 miscroscale probe spacings were used to measure the resistivity of the surface layers
An algorithm for computing linear fourpoint probe thickness correction factorsEdit
Robert A. Weller, "An algorithm for computing linear fourpoint probe thickness correction factors," Review of Scientific Instruments, 72(9), 35803586, 2001.
 Confirms the foundational work by Valdes in computing correction factors
 Combines various other works into a single formula for computing correction factors
 different forms of varying accuracy and computational expense are given
 a permutation of the formula is given for samples with a conducting substrate
 loses accuracy as t/s > 0
Direct measurement of surfacestate conductance by microscopic fourpoint probe methodEdit
Shuji Hasegawa, Ichiro Shiraki, Takehiro Tanikawa, Christian L. Petersen, Torben M. Hansen, Peter Boggild, Francois Grey, "Direct measurement of surfacestate conductance by microscopic fourpoint probe method," Journal of Physics: Condensed Matter, 14(35), 8379, 2002.
 best description of surface layer conductance yet
 Describes the three paths current from a 4PP follows through a sample
 describes how these paths are affected by probe spacing
 micro 4PP can measure specific areas of a sample
 useful if you want to avoid/investigate certain defects
 useful if you want an extremely detailed conductivity map
 tests were run in a UHV chamber on a silicon substrate to validate
 a deposition of one atomic layer of Ag reduced surface resistance by two orders of magnitude
 an explanation of how probe separation affects sheet resistance measurements is given
 charge carriers have a lower mobility on the surface of a substrate
 the authors account for the influence of atomic stepping on their measurements
 methods are used to transport steps until they form straight terraces
 micro 4PP measurements can then be taken in stepfree or stepclustered regions
 steps are shown to increase surface resistance
 micro four point probe as a novel tool to investigate surface state conductance; electronic transport in nanometre scale object
 mentioned four point probe as a way to avoid contact resistance when measuring materials
VariableTemperature MicroFourPoint Probe Method for Surface Electrical Conductivity Measurements in Ultrahigh VacuumEdit
Takehiro Tanikawa, Iwao Matsuda, Rei Hobaru, Shuji Hasegawa, "VariableTemperature MicroFourPoint Probe Method for Surface Electrical Conductivity Measurements in Ultrahigh Vacuum," eJournal of Surface Science and Nanotechnology, 1, 5056, 2003.
 Concerns with surface electrical conductivity measurements
 Scanning tunneling microscope enables precise probe positioning for micrometer probe spacing
 To measure the electrical characteristics of surface layers, probes need to be really close together
 This paper describes how to manufacture and use probes with ~um spacing
 Measurements were performed in a temperaturecontrolled UHV chamber
 An excellent description of electronics is given
Reduction of positional errors in a fourpoint probe resistance measurementEdit
D. C. Worledge, "Reduction of positional errors in a fourpoint probe resistance measurement," Applied Physics Letters, 84(10), 16951697, 2004.
 Focuses on microscopic four point probe. They are prone to positional errors
 cites article that claims resistance errors are dominated by positional errors
 there are three permutations of +/I and +/V mappings on the probes that provide useful information
 by utilizing more measurements, some errors can be canceled out
 formulas are given to achieve this
 the crappier the probe, the greater the improvement
Null method for fourpoint probe measurement using high resistance probesEdit
Makoto Ishikawa, Masamichi Yoshimura, Kazuyuki Ueda, "Null method for fourpoint probe measurement using high resistance probes," eJournal of Surface Science and Nanotechnology, 4, 115117, 2006.
 suggests a method for performing 4PP measurements with very high resistance probes
 The method basically is about trying to adjust some voltage source until the current becomes zero. By calculating zero point from two points, resistivity could be derived
 measures current through both pairs of probes, and performs some math to produce a measurement
 electronics used are a PCI3523A (D/A converter) and a Keithley model 486 picoammeter in a SEM
 method matches values obtained by a commercial unit
FourPoint Probe Resistance Measurements Using PtIrCoated Carbon Nanotube TipsEdit
Shinya Yoshimoto, Yuya Murata, Keisuke Kubo, Kazuhiro Tomita, Kenji Motoyoshi, Takehiko Kimura, Hiroyuki Okino, Rei Hobara, Iwao Matsuda, Shinichi Honda, Mitsuhiro Katayama, Shuji Hasegawa, "FourPoint Probe Resistance Measurements Using PtIrCoated Carbon Nanotube Tips," Nano Letters, 7(4) 956959, 2007.
 measuring electrical properties of nanoscale materials is tough
 electrical contacts are difficult to attach
 contacts can damage the sample and/or the probe
 carbon nanotubes make good probes
 their resistance can be made more reliable using a conductive coating
 they cause no electrical/mechanical damage to the sample, even after repeated use
 2point method flawed due to difficulty in controlling contact resistance
 could not measure resistance less than 50kOhm
 4point could measure as low as 2Ohm
 Some stuff about tip construction, not important
 stuff about experimental setup
 the 4PP measurements were performed by running a DC sweep between tips 1 and 4, while measuring the current through tips 1 and 4, and the voltage across tips 2 and 3.
 a 1e6(A/V) preamplifier was used to detect the current
 current was as large as 2uA
 voltage measurement current was less than 0.1pA; negligible
 a 1e6(A/V) preamplifier was used to detect the current
 Tip 3 was shifted to adjust the tip spacing.
 this changed the measured resistance
 the resistance changed linearly due to the fact that the measured object is a wire; the current can only travel in a straight line
 this changed the measured resistance
 the CNT tips did not deform, even after repeated use
Correction factors for 4probe electrical measurements with finite size electrodes and material anisotropy: a finite element studyEdit
E. J. Zimney, G. H. B. Dommett, R. S. Ruoff, D. A. Dikin, "Correction factors for 4probe electrical measurements with finite size electrodes and material anisotropy: a finite element study," Measurement Science and Technology, 18(7), 2067, 2007.
 getting accurate resistivity measurements is hard because you need to put in enough current for the voltage drop to be meaureable
 4PP as a method to eliminate contact resistance
 This paper studies 4PP with large electrode that span the sample's surface
 finite element analysis is used to determine correction factors
 assumes linear IV curve and homogeneous resistivity
 studies anisotropic resistivity measurements with a 4PP (useful for perovskites!)
 matlab is used to perform FE calculations
 studies effect of interface resistance on the measured voltage
 the effect of electrode size is studied
 for thin samples, electrode size is mostly irrelevant
 anisotropic properties lead to a change in the thicknes of material being measured
 large electrodes effect the measurement
Enhancing repeatability in the measurement of potential drop using an adjustable fourpointprobe measuring system (*)Edit
S. Reaz Ahmed, "Enhancing repeatability in the measurement of potential drop using an adjustable fourpointprobe measuring system," Research in Nondestructive Evaluation, 18(2), 69100, 2007.
 Looking for article
Microfourpoint probe Hall effect measurement methodEdit
Dirch H. Petersen, Ole Hansen, Rong Lin, Peter F Nielsen, "Microfourpoint probe Hall effect measurement method," Journal of Applied Physics, 104(1), 013710, 2008.
 describes a nondestructive way to perform halleffect measurements on a semiconductor
 uses a 4PP to individually measure carrier sheet density and mobility
 describes 4PP theory
 analysis is restricted to thin films with insulating boundaries
 a magnetic field is applied to the sample, followed by a 4PP measurement
 magnetic field is generated by a permanent magnet
 note: could the magnetic bearings in our 3d printer system affect measurements?
 using some formulas, the carrier mobility and density can be determined from this experiment
 magnetic field is generated by a permanent magnet
 used a CAPRES microRSPM150 system
 highly doped ptype silicon and germanium samples were tested
 a series of 4PP tests were run at varying distances from the insulating boundary
Accurate microfourpoint probe sheet resistance measurements on small samplesEdit
Sune Thorsteinsson, Fei Wang, Dirch H. Petersen, Torben Mikael Hansen, Daniel Kjaer, Rong Lin, JangYong Kim, Peter F. Nielsen, Ole Hansen, "Accurate microfourpoint probe sheet resistance measurements on small samples," The Review of Scientific Instruments, 80(5), 053902, 2009.
 Links several articles referring to correction factors
 reviews sheet resistance theory
 use of dual configuration probes is discussed
 this measurement style reduces the effect of boundaries for circular samples
 discusses formulas for measuring the sheet resistance of small (a few times the probe pin pitch) samples
 also discusses proper measurement techniques for such samples
 discusses use of dual configuration M4PPs to ease measurement
 in some cases correction factors are unecessary
Four point probe geometry modified correction factor for determining resistivityEdit
F. Algahtani, K. B. Thulasiram, N. M. Nasir, A. S. Holland "Four point probe geometry modified correction factor for determining resistivity," Proceedings of SPIE  The International Society for Optical Engineering, December 2013
 Using computer modelling to simulate how correction factor varies with sample size and sample thickness
 correction factor does not vary significantly if probe spacing is greater or equal to 8 times the sample thickness. Default correction factor 4.54 could be used in this case
 Correction factor for probes near boundaries vary more on a circular sample than on a square sample
 For square sample if distance to edge is greater or equal to 5 times the probe spacing, correction factor doesn't vary much
 For circular sample, if distance to edge is greater or equal to 14 times the probe spacing, default correction factor will work
The 100th anniversary of the fourpoint probe technique: the role of probe geometries in isotropic and anisotropic systemsEdit
I. Miccoli, F. Edler, H. Pfnür, C. Tegenkamp, "The 100th anniversary of the fourpoint probe technique: the role of probe geometries in isotropic and anisotropic systems," Journal of Physics: Condensed Matter, 27(22), 223201, 2015.
 four point probe for resistivity measurement; four point probe as an established method throughout industry; four point probe method dependent on probe position and boundary condition
 two probe vs four point probe; contact resistance
 Formulas (correction factor) for relating measured resistance to resistivity in 3D semi infinite bulk, 2D infinite sheet or finite 3D or 2D
 Correction Factor divided into 3 : taking account finite thickness of sample, alignment of probes near sample edge, finite lateral width
 Van der pauw method for measuring arbitrary shapes
 Review of methods to measure anisotropic materials
 Mentioned that the formula is derived assuming point contact between probe and material, if not other more complex formula must be used
 A lot of references to other paper
Four Point Probe standardsEdit
ASTM F152997Edit
Standard Test Method for Sheet Resistance Uniformity Evaluation by InLine FourPoint Probe with the DualConfiguration Procedure
Has been withdrawn, no replacement
 for measuring sheet resistance and its variation
 designed for circular silicon wafers of any size
 other shapes can be measured, but correction factors need to be included
 may give misleading results if the silicon is formed on an insulator
 can measure from 10mOhms for metal films to 25kOhms for silicon films
 inline 4PP takes resistivity measurements at multiple locations
 measurements are taken with current going both directions to eliminate thermoelectric effects
 before the probe is raised, another measurement is taken, but with the role of each probe changed
 measurements should be performed in the dark unless the material is light insensitive
 if minority carrier injection is an issue, run at lower current
 low current also reduces resistive changes due to heating
 device should be vibration isolated
 lightly doped semiconductors can cause erroneous readings
 recommendations are given for various probe types
 a microscope and hot plate is recommended
 constantcurrent source must be able to produce enough current to drop 5 to 20mV across the specimen
 currents between 1e6 and 1e2A are required if Rsheet is between 1 and 20kOhm
 output must be stable to 0.01% or better
 ripple and noise must be less than 0.1% of dc level
 standard resistor should be b/n 2.5 to 25 times the sheet resistance
 know value of standard resistor to 4 sig figs
 voltmeter should read b/n 1 and 100mV, and resolve to 0.01% or better
 input impedance should be 1e9
 make sure the probe doesn't destroy the sample when you first build it
 some testing procedures are detailed
 sheet resistance calculations are detailed
ASTM F8402Edit
Standard Test Method for Measuring Resistivity of Silicon Wafers With an InLine FourPoint Probe
has been withdrawn, no replacement
 Watch out for voltmeters that emit small currents for auto testing
 for sheet resistivities over 1000 Ohmcm, these currents ca cause erroneous measurments
 can be accounted for by using forward and reverse measurements
ASTM F81 (*)Edit
Test Method for Measuring Radial Resistivity Variation on Silicon Slices
Looking for article
Has been withdrawn, no replacement
ASTM F374 (*)Edit
Test Method for Sheet Resistance of Silicon Epitaxial, Diffused, Polysilicon, and IonImplanted Layers Using an InLine FourPoint Probe
Looking for article
ASTM F1241 (*)Edit
Terminology of Silicon Technology
Looking for article
An international Comparison Measurement of Silicon Wafer Sheet Resistance using the Fourpoint Probe MethodEdit
JeonHong Kang, GaoYing, YuhChuan Cheng, ChangSoo Kim, SangHwa Lee and KwangMin Yu, "An international Comparison Measurement of Silicon Wafer Sheet Resistance using the Fourpoint Probe Method," Journal of Electrical Engineering and Technology, 10(1), 325350, 2015.
 summarizes standard 4PP measurement techniques
 meant for thin films for semiconductor, touch panel, and touch screen processes
 summarizes standard equations and correction factors needed for single and double configuration inline 4PP's
 Various groups tested the measurement procedures and validated for accuracy, but it's not too important
Four Point Probe designsEdit
a description of the electronics used for measurents is given in this paper.
An AC Bridge for Semiconductor Resistivity Measurements Using a FourPoint ProbeEdit
M. A. Logan, "An AC bridge for semiconductor resistivity measurements using a fourpoint probe," Bell System Technical Journal, The, 40(3), 885919, 1961.
 describes a measurement circuit that measures the ratio between voltage and current of a 4PP, and thus the resistivity
 60's era analog magic
 builtin calibration
 describes a system that's entirely grounded, ac operated, and devoid of meters save for an ac null detector
 constant current source is unnecessary
 independent of frequency
 precision amplifiers are necessary
 describes steps that need to be taken for various resistivity levels
 goes into the effect of constriction resistance
 is sensitive to probe contact resistance
 thermal noise and parasitic probe capacitance is accounted for
Design of intelligent fourpoint probe meter (*)Edit
 Looking for paper, but may not be able to find english version
Four point probe method based on LOG112 and C8051F006 SoCs for resistivity measurementEdit
R. Ewakita, E. Rahmawati, k. Mikrajuddin Abdullah, "Four point probe method based on LOG112 and C8051F006 SoCs for resistivity measurement," 2009 International Conference on Instrumentation, Communications, Information Technology, and Biomedical Engineering (ICICIBME), pp. 13, 2009.
 indepth discussion of 4PP electronics
 uses SystemonaChip's (SoC) to simplify design
 a microcontroller is used to produce the current via control of a DAC (with feedback from the ADC)
 a fluke voltmeter is used to measure voltages
 this is used to calibrate the DAC as well as measure inner terminal voltage
Design, implementation, and assessment of a highprecision and automation measurement system for thin film resistivityEdit
Pan Haibin, Ding Jianning, Wang Xiaofei, Li Boquan, "Design, implementation, and assessment of a highprecision and automation measurement system for thin film resistivity," 2010 International Conference on Mechanic Automation and Control Engineering (MACE), pp. 22352238, 2010.
 Investigates technology to improve automated resistivity measurements
 discusses dualconfiguration probe configurations
 uses expensive NI hardware for PC>circuit interface
 keithley 2400 sourcemeter serves as a DAC and ADC
 uses labview for controls
 details a switch used to operate the dualconfiguration modes
 ^^Really cool chip! CD4052
 allows one to swap the functions of the probes in any way
Design and Characterization of a Four Point Probe for Conducting Polymer Electrode Studies (*)Edit
L. J. Holtzknecht, H. B. Mark Jr., T. H. Ridgeway, H. Zimmer, Design and Characterization of a Four Point Probe for Conducting Polymer Electrode Studies", Instrumentation Science & Technology, 18(1), 2335, 1989.
 looking for article
Commercial ReviewEdit
I'm focusing on devices with similar capabilities to the device being planned
 resistivity measurement capabilities
 automatic measurement at a large amount of programmable points
 support for at least 300mm wafers
 Keep the commercial quotes off the wiki.