Drieterminalmetingen

Drieterminalmetingen, also known as three-terminal measurements, are a fundamental technique used in electronics and physics to characterize the electrical properties of materials and devices. This method involves using three electrical contacts to a sample, allowing for a more precise determination of resistance and other electrical parameters compared to simpler two-terminal methods.

The primary advantage of a drieterminalmeting lies in its ability to eliminate or significantly reduce the influence of contact resistance and lead resistance. In a two-terminal measurement, the measured resistance includes not only the resistance of the sample itself but also the resistance at the interfaces between the contacts and the sample, as well as the resistance of the wires connecting the sample to the measuring instrument. These parasitic resistances can often be substantial, leading to inaccurate results, especially when measuring low-resistance samples.

In a drieterminalmeting, one terminal (often referred to as the "sense" or "voltage" terminal) is placed close to the current injection point but not directly on it. Current is passed between two other terminals (the "source" and "sink" or "current" terminals). The voltage drop is then measured across a specific section of the sample using the current terminals or a separate set of voltage probes. By employing a high-impedance voltmeter, the current flowing through the voltage measuring circuit is negligible, meaning the voltage drop measured is primarily due to the resistance of the sample itself, with the contact and lead resistances to the voltage probes having minimal impact.

This technique is widely used in semiconductor research for measuring the resistivity and mobility of thin films and bulk materials. It is also crucial in the characterization of components like transistors, where understanding the resistance of specific regions is vital for performance analysis. The precision offered by drieterminalmetingen makes them indispensable for accurate electrical characterization in various scientific and engineering disciplines.