Neliövastusmittaus

Neliövastusmittaus, also known as sheet resistance measurement, is a technique used to characterize the electrical properties of thin films and surfaces. It is particularly useful for materials with a relatively uniform thickness, such as conductive coatings, semiconductor layers, and metallic films. The method determines the resistance of a square section of the material, regardless of its actual size, by measuring the voltage drop across a known current.

The measurement is typically performed using a four-point probe setup. Four collinear probes are pressed onto the surface of the material. A current is passed through the two outer probes, and the voltage drop is measured across the two inner probes. This configuration minimizes contact resistance effects, which can significantly influence the accuracy of two-point measurements. The sheet resistance is then calculated using a specific formula that takes into account the probe spacing and the measured voltage and current.

The unit of sheet resistance is ohms per square (Ω/□). A low neliövastusmittaus value indicates a highly conductive material, while a high value suggests poor conductivity. This technique is widely employed in various fields, including semiconductor manufacturing for quality control of doping levels and film uniformity, as well as in the development of new electronic materials and transparent conductive films. It provides a simple yet effective way to assess the electrical integrity and uniformity of thin conductive layers.