Using a collinear four-probe array, this test method measures the sheet resistance of metallic thin films. Procedures for inspecting the electrical measuring device and the probe assembly are part of this test technique. MaTestLab is one of the best testing service providers, with the best network of testing laboratories in the USA to carry out ASTM F390 tests for our clients. By measuring the indentations that the points make on an appropriate surface, the distances between the four probe tips are determined. The state of the tips is also assessed using this technique.
ASTM F390 Test Method
| Probe Function | In ASTM F390, a collinear four-probe array is used to compute the sheet resistance by passing a measured direct current through the specimen between the outer probes and measuring the resulting potential difference between the inner probes. |
| Resistor Function | The accuracy of the electrical measurement apparatus is evaluated using an analog circuit that consists of a known standard resistor and additional resistors that mimic the resistance at the contacts between the probe tips and the film surface. |