Four Point Probes

  Bridge Technology
  Tel: (480) 988-2256     Fax: (480) 452-0172     E-mail: sales@bridgetec.com

 

Home Frames Version for easier navigationProducts Tech Info FAQ Contact  
Technical Information

1 Short Application Note on Sheet Resistance, Ohms-Per-Square, and the Calculation of Resistivity or Thickness

2 Basic information regarding how to make four point probe measurements using Jandel resistivity test equipment.

3 Four Point Probe Theory - A helpful article

4 Four Point Probe Equations - A helpful article from the      University of Illinois - Urbana/Champaign

5 Understanding volume resistivity measurements and converting between ohms-per-square (sheet resistance) and ohms-cm (volume resistivity)

6 Sample Size Requirements and Correction Factors Some questions and answers from Jandel Engineering Ltd.

7 Haldor Topsoe Technical Documents Regarding Correction Factors Correction Factor for various material shapes and sizes

8 1964 National Bureau of Standards Technical Note 199, "Correction Factor Tables for Four-Point Probe Resistivity Measurements on Thin, Circular Semiconductor Samples"

9 Finite-Size Corrections for 4-Point Probe Measurements, by J. R. Senna, Instituto Nacional de Pesquisas Espaciais (INPE), Brasil

10 Questions and answers re: resistivity & resistance, sheet resistance, volume resistivity, surface resistivity by John Clark of Jandel Engineering

11 Q & A regarding the use of Jandel Resistivity Measurement equipment by Pete Clark of Jandel Engineering

12 Four-Point Probe Theory of Operation from the University of California, Berkeley, EECS web site (PDF file)

13 A table of suggested probe tip specifications for various silicon wafer types.

14 A table of common four point probe tip radii and spacings

15 Osmium alloy tips versus tungsten carbide tips

16 Square array versus linear array four point probe

17 Reversing current to check the validity of a 4 point probe measurement

18 Determining the best choice of probe tip specifications (tip spacing, spring loads, material, radii) for a given material.

19 What is the expected life of a Jandel Four Point Probe Head?

20 Jandel FAQ

Hall Effect Measurement Technical info:

21 Wikipedia article regarding the Hall Effect

22 Wikipedia article regarding the Van der Pauw method

23 NIST web page regarding the theory and implementation of the Hall Effect Measurement technique

 

Square Array Four Point Probe

Square Array versus Linear Array Four Point Probe

 

The square array four point probe has some differences to consider when compared to the much more commonly used linear array four point probe:

 

  1. When measuring a thin film using a square array probe, the voltage signal is one-half of the voltage compared to a linear array probe. Therefore when using a square array probe, you cannot use the ohms/square button on the RM3-AR to provide a valid sheet resistance. To calculate an ohms-per-square value, the formula is 4.5324 x 2V/I (rather than V/I), however, by using a suitable current, the math involved can be minimized. Square array probes are not usually used on bulk materials (e.g., ingots) since the main advantage is the smaller footprint which allows the four tips to fit on a smaller material. The rule of the voltage signal being 50% of that when using a linear array does NOT apply when measuring bulk materials. For further information about using a square array probe on bulk materials, please see the article by S. B. Catalano, Correction Factor Curves for Square-Array and Rectanglular-Array Four-Point Probes Near Conducting or Nonconductivin undaries"
  2. The wiring arrangement for square layout produces a negative voltage in the FWD direction and a positive voltage in the REV direction. This does not mean there is a fault and the sign can be discounted to compare the FWD and REV values.
  3. Square and rectangle arrays can only be built with needle spacing from 0.635mm up to 1.591mm, not close needle spacing of 0.5mm.
  4. The Jandel probe models that can be built using the square array are the Cylindrical probe, Six-Way probe (both CDE and KLA-Tencor/Prometrix models), Four-Pin probe, and the Cartridge with Lead probe


The smaller footprint allows smaller samples to be measured. When probing onto wafers, the use of a square array probe allows the user to measure closer to the edge of a sample before a correction factor is required. The smaller voltage signal must be taken into account when using four point probing electronics and software that are designed to calculate sheet resistance and to read-out directly in ohms-per-square based upon the assumption that a linear array probe is being used.



Jandel references these papers related to square array probes in their various instruction manuals:

Small slice at centre:
A. Marcus and J. J. Oberly, IEEE Trans. Electron. Devices, ED-3, 161 (1956)

Small slice along a radius:
L. J. Swartzendruber, National Bureau of Standards Technical Note 199 (1964)

Square sample:
M. G. Buehler, Solid State Electronics, 10, 801 (1967)

Thick sample near boundary:
S. B. Catalano, IEEE Trans. Electron. Devices, ED-10, 185 (1963)

Thin infinite sheet:
M. G. Buehler, Solid State Electronics, 10, 801 (1967)

 

 


Four-Point-Probes is a division of Bridge Technology. To request further information please call Bridge Technology at (480) 988-2256 or send e-mail to Larry Bridge at: sales@bridgetec.com

 

 

 

  We accept credit cards!

HOME   l   PRODUCTS   l   TECH INFO   l   FAQ   l   ABOUT   l   CONTACT

Copyright © 2009 Four-Point-Probes. Powered by Bridge Technonlogy.