FYTRONIX Hall effect systems measure electrical properties of semiconductor materials 

0.55Tesla permanent magnet (+/-0.03Tesla)

Conductive sample mounting board

System automatically measure

Mobility 

Carrier concentration

Resistivity

Hall coefficient

Conductivity

Sheet resistance

Four probe resistance measurement

Measurement ranges:

- resistivity range: 10-4 to 107 Ohms-cm

- Hall voltage range: 1µV to 2000 mV

- mobility: 1 to 107 cm2/V.s

Density (cm-3): 107 ~ 1021

Magnet : Permanent magnet (diameter: 50mm)

Magnet Flux Density: 0.55T nominal +/-1% of marked value Stability: 2% over 1 years Uniformity: +/- 1% over 20mm diameter from center Pole Gap: 26 mm

Current source: Range: 1nA-20mA Compliance: 12V

Sample holder: Sample board 

Electronic Contact switching card

THE VAN DER PAUW METHOD

The van der Pauw Method is a technique commonly used to measure the sheet resistance and the Hall Coefficient of a sample. Its power lies in its ability to accurately measure the properties of a sample of any arbitrary shape, so long as the sample is approximately two- dimensional (i.e. it is much thinner than it is wide) and the placement of the electrodes is known.

From the measurements made, the following properties of the material can be calculated:

♦ The sheet resistance, from which the resistivity can be inferred for a sample of a given thickness.

♦ The doping type (i.e. if it is a P-type or N-type) material.

♦ The sheet carrier density of the majority carrier (the number of majority carriers per unit area). From this, the density of the semiconductor, often known as the doping level, can be found for a sample with a given thickness.

♦ The mobility of the majority carrier.