The four point probe at the Solar Power Laboratory is a Signatone S 302-8. The tool measures bulk resitivity (ohm-cm) and sheet resistivity (ohm/square) of wafers and diffusions. A custom LabVIEW program provides the user interface and drives the power supply. Accuracy and repeatability is greatly improved by a linear regression fit to a large range of bias voltages.
This tool is available to external users for a reasonable fee. Please contact us for further details.