How to Measure Silicon Wafer Resistivity with 4-Point Probe

Key Takeaways: Semiconductor Metrology

  • Non-Destructive Testing: The 4-point probe method is the industry standard for measuring resistivity of silicon substrates and thin films.
  • Surface Sensitivity: Probes can mar polished surfaces; non-contact gauges are recommended for final wafer characterization.
  • Accuracy Factors: Precise resistivity calculations require accounting for sample thickness and temperature coefficients.
  • Error Mitigation: Success depends on managing contact resistance, surface contamination, and probe alignment.
UniversityWafer Logo - Semiconductor Substrate Experts

4-Point Probe Colinear Measurement

A postdoc requested an answer to the following question:

I am looking to purchase a wafer that can be used as a 4 point colinear measurement standard. Meaning that we have a known material of a certain size with a known sheet resistance.

UniversityWafer Replied:

I suggest to use the wafers with the narrowest resistivity ranges. We offer them in practically each resistivity range.

Reference #245648 for specs/pricing.

Get Your Quote FAST! Or, Buy Online and Start Researching Today!

4-Point Probe FIB Resistance Measurements

A senior technology leader requested a quote for the following.

Question: I was wondering if you guys sell wafers that have structures for taking 4-point measurement to measure resistance of a Focused Ion Beam deposited line?

Answer: We can make 4-point measurement for resistivity on 100mm diameter substrates with laser markers.

100mm silicon wafer with 500nm Copper and Chromium thin films for 4-point probe calibration

4-Point Probe Metrology: Key Concepts

Metrology Term Application
Sheet ResistanceCharacterizing thin films and conductive coatings.
Contact ResistanceMitigating errors between probe tips and sample surface.
Non-Contact GaugesMetrology used to avoid marring polished wafer surfaces.

Silicon Wafer Resistivity Measurement FAQs

Question: Is a silicon wafer's resistivity measured from the polished surface?

Answer: A silicon wafer ideally has uniform resistivity throughout its body. However, a 4-point probe can damage a polished surface; therefore, non-contact resistivity gauges are often used for final characterization of polished wafers.

High-resolution surface map of silicon layer showing resistivity distribution for homogeneity testing

Common Errors in GaAs Resistivity Testing

When measuring Gallium Arsenide (GaAs) using the 4-point probe method, common sources of error include contact resistance, inhomogeneous material, surface contamination, and probe misalignment.

Four-point probe head assembly with tungsten carbide tips for semiconductor sheet resistance measurement

What is a Vertical Tunnel Diode?

A vertical tunnel diode exhibits negative differential resistance (NDR) via quantum tunneling. Current flows vertically through stacked p-n junction layers, offering benefits in high-frequency oscillators and fast switches.