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

 

About Jandel Engineering Ltd.

About Jandel Engineering and Jandel Four Point Probing Equipment

 

About the Company
Jandel Engineering was established in 1967. Prior to founding Jandel Engineering, Managing Director John Clark worked for A & M Fell in London. It was at this company that the first commercially available four point probe head, the 'Fell' probe head, was designed by John Clark and a colleague. Since this original design many improvements have been introduced.

Q. Who makes Jandel's probes?


Experts! All probe heads are made by experienced engineers with a minimum of six years intensive training. Some of our probe builders can boast nearly 20 years experience.

 

 

Q. Why use Jandel probes?


Jandel Probes offer the accuracy and perfection of more than 40 years experience. Tip radii and probe spacings are checked by interferometer and video inspection for certainty of accuracy. Spring loadings are checked by electronic force gauge.

 

Unique Standard specifications include:

 

  • Upper and lower guides are jewelled
  • Solid tungsten carbide needles for superior durability and accuracy
  • Teflon insulation giving minimum leakage

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    Q. What model of probe should I use?


    A. Jandel has many different shapes of probe heads. The best one for you depends entirely on your application and what machine (if any) you are using. Contact us with details of the probe you have now and we will let you know the best probe for you. Alternatively, if you wish to make a custom set up, we can help you to identify which probe will work best.

     

     

    Q. Why are there so many different characteristics?

     

    Different users wish to probe different items, which means it is necessary to provide a wide range of characteristics. For instance someone wishing to measure a layer beneath an oxide would need sharp probes to penetrate the oxide layer, whereas a very thin metallic layer may require a much larger radius on the needles so that they do not puncture the layer. Similarly, some spacings are designed in order to help with the maths involved in working out resistivity, someone else may just require a very close spacing probe in order to fit all the probes on the sample.

     

    Q. Which probe tip specifications should I use?

     

    The characteristics needed vary depending on the material being probed. If you contact us we may be able to advise the best characteristics for your samples from past experience. Alternatively you have the option of sending us a typical sample of the material you wish to probe and we will test it so that you can be sure to receive the best characteristics for your application. There is no charge for this service. More about the choice of probe tip specifications can be found here. Determining the Best Choice of Probe Tip Specifications for a Given Material

     

     

     

    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