Used to measure the resistivity and sheet resistance of silicon wafers, epitaxial layers, diffusion layers, ITO, ion implantation layers, metal films, etc.
Principle
The four-probe test technology uses four equally spaced probes to penetrate the surface of the material. A constant current source provides current I to the two outer probes, and the voltage V between the two middle probes is measured to calculate the resistivity and sheet resistance.
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