Linear Four Point Probe

Description

Four point electrical measurements are utilized to more accurately determine the sheet resistance of bulk samples or thin films because they can eliminate the effect of contact resistance. The repeatable contact force, simplified geometry, ease of specimen mapping, and measurement rapidity are the principle advantages of this modified van der Pauw technique for determining bulk resistivity. The user can measure sample resistance spanning more than 12 orders of magnitude by configuring the electrical biasing and measurement scheme. A simple and intuitive graphical user interface (GUI) is utilized to control the measurement parameters via Keithley KickStart Software.

Capabilities

Jandel Four Point Probing System
- Max sample diameter: 200mm
- Max sample thickness: 2mm
Keithley 8009 high resistivity test fixture
- volume and surface resistivity measurements
- Sample size: 64mm to 102mm (2½ to 4 in) in diameter
- Max sample thickness: 3.2mm (1⁄8in)
Keithley 2450 Source Meter
- Voltage ranges: 20mV – 200V (42V max without interlock)
- Current ranges: ±1A (up to ±20V), ±100mA (up to ±200V)
Keithley 6514 System Electrometer
- Voltage range: ±10µV to ±210V
- Current range: ±100aA to ±21mA
- Resistance range: 10mΩ to 210GΩ
- Electric charge range: 10fC to 21μC

Comparison Table

Restance Range (R)	Technique	Equipment Configuraton
10mΩ < R < 2 Ω	Low-Resistance Mode	Keithley 2450 SMU; Jandel 4PP, Keithley 6514 system electrometer (if you need to measure in 10mΩ range)
2 ≤ R ≤ 200MΩ (Normal range of operation)	Normal Mode of Operation	Keithley 2450 SMU; Banana jack to alligator clip connectors; Jandel 4PP
200MΩ < R ≤ 210 GΩ	High-Resistance Mode	Keithley 2450 SMU, Keithley 6514 system electrometer, Jandel 4PP and or 8009 High-Resistivity Test Fixture

Example Data

Location: RFM 2226
Manager: Dr. Casey Smith, casey.smith@txstate.edu
Backup: Jacob Armitage, jacob.armitage@txstate.edu
Trainer: Daniel Bailey, d_b587@txstate.edu
Model: Jandel stage, Keithley 2450 SMU