Four-point probe measuring instrument

The purpose of the four point probe is to measure the resistivity of any semiconductor material. It can measure either bulk or thin film specimen, each of which consists of a different expression.

• Highly repeatable needle contact conditions owing to controlled velocity of descent;
• Individually adjustable needle loadings with direct indication of set load;
• Solid tungsten carbide needles with precision radiused tips;
• Fully visible contact area;
• Micrometer controlled slice displacement;
• Hinged steel cover to eliminate effects of light and electrical interference during measurement;
• Specification – probe needles:
  • Material: 0.5 mm diameter tungsten carbide, 26 mm long, 45 degree included angle, 25 micron tip radius (or larger up to 100 microns);
  • Spacings: 1.00 mm, 1.27 mm, 1.59 mm – tolerance +/- 0.01 mm;
  • Travel 4 mm;
  • Insulation resistance: 2 x 105 megOhms at 500 volts;
  • Load: 0-100 grams applied by adjustable individual tension gauges;
  • Specimen: slice only, 76 mm diameter is normal maximum.