The most common technique used for measuring sheet resistance is the four-probe method. This technique involves using four equally-spaced, co-linear probes (known as a four-point probe) to make electrical contact with the material. Most four-point probes available commercially use sharp needles as probes.
What is 4 point probe method?
Four-point probe measurer (FPP) is a tool that is commonly used to measure resistivity value of a layer of an electronic material, that is, semi-conductor material such as silicon (Si), Germanium (Ge), Ballium Arsenide (GaAs), as well as metallic material in thin film (thin layer) that is used in electronic devices.
How do you use a 4 point probe?
The following steps should be taken in the following sequence:
- Turn on the voltmeter, set the mode to DC and voltage range to 200 mV.
- Place wafer onto the probe stage.
- Flip the toggle switch located atop the probe station from “NEUTRAL” TO “DOWN”.
- Watch the probe casing lower until the probes stabilize on the wafer.
