4 Point Probe

Description

The 4-point probe method is a technique used in materials science and electrical engineering to measure the resistivity of thin films and bulk materials. It involves four evenly spaced probes that contact the material surface, forming a square or diamond configuration. By passing a known current through the outer probes and measuring the resulting voltage drop across the inner probes.

The resistivity of the material can be calculated using the formula:

ρ=VI⋅dA\rho = \frac{V}{I} \cdot \frac{d}{A}ρ=IV​⋅Ad​

where:

• $\rho$ is the resistivity of the material,
• $V$ is the voltage measured between the inner probes,
• $I$ is the current passing through the outer probes,
• $d$ is the distance between the probes,
• $A$ is the cross-sectional area of the material under the probes.

This method is particularly useful for characterizing semiconductor materials, thin films, and other conductive materials with known geometries. It provides a non-destructive and precise way to determine resistivity, which is crucial for evaluating the electrical properties of materials used in various electronic devices and components.