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

 

Four Point Probe Tip Specifications Applications Chart

Four Point Probe Tip Specifications Applications Chart

 

The following reference guide (developed by Prometrix for the OmniMap system) suggests the best four point probe tip specifications for a variety of silicon wafer types. We offer the service of testing wafers/materials to determine the optimum tips specifications. Please contact Bridge Technology for further information.

TC=tungsten carbide tip material. Osmium alloy tips are also available, but are rarely justified.

Please note that this chart was developed decades ago when silicon wafers were less advanced in design and materials. For example, the reference to using a type "A" probe for "metals" refers to probing aluminum which was the primary metal used on silicon wafers. The 1.6 mil (40 micron) sharp tips recommendation was to punch through native aluminum oxide. However, this did not take into consideration the use of other metals such as copper, nor that fact that some very thin aluminum layers (e.g., 50nm) are probably more suited for measurement with a type B or C probe which has a larger tip radius. Metals such as copper can also be successfully measured with a larger tip radius which leaves less marking on the surface and should provide for longer tip life.

 

PROBE TYPE
TIP RADIUS
SPRING LOAD
MATERIAL
SPACING
APPLICATION
A

F
1.6 mils

1.6 mils
100 grams

100 grams
TC

TC
40 mils

25 mils
For measuring metals
B

G
4.0 mils

4.0 mils
100 grams

100 grams
TC

TC
40 mils

25 mils
General purpose head for implantation, doped poly, epitaxy, diffusion.
C

H
8.0 mils

8.0 mils
100 grams

100 grams
TC

TC
40 mils

25 mils
For high impedance surfaces such as low implant doses and shallow junctions.
D
20 mils
100 grams
TC
40 mils
For very difficult implant and high impedance surfaces beyond the 8.0 mil
E
1.6 mils
200 grams
TC
62.5 mils
For substrate measurements

Click here for information regarding replacement four point probe heads
for Prometrix and or KLA/Tencor resistivity wafer mapping systems.

 

 

 


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