Options for the Model 8425
Extra probe arms for Hall bar measurements
As standard, the Model 8425 system ships with four probe arms installed in the system for van der Pauw measurements. To also perform Hall bar measurements, the 84-HBM option provides two extra probe arms, probe arm cabling, and mounts.
PS-HV-8425 high-vacuum kit option
This option is for applications requiring even lower base pressures than what’s possible with the vacuum system included in the standard Model 8425 probe station. With a vacuum to <5 × 10-7 Torr while the station is at base temperature, it represents an improvement of two orders of magnitude over the standard vacuum. It is recommended for samples highly sensitive to contamination or condensation during cooldown. And, with it, you can reduce pump-down time by about 30%.
Zoom 125 optics vision system option
The vision system on the Model 8425 probe station features 7:1 zoom optics with a high-sensitivity, color CCD camera and a monitor. The camera is specifically chosen for low light sensitivity to minimize the lighting required for high image quality. However, if you need greater magnification of a sample under test, an optional vision system is available to boost the camera’s capabilities to 12.5:1 zoom optics. The lens fastens to the CCD camera shipped with the Model 8425 system.
84032P gate bias option
With this option, the gate bias voltage can be set to the user-determined value, increasing the flexibility of the Hall measurement. For instance, a gate voltage can be used to control the carrier density of a material. The option includes a Keithley Model 6487 picoammeter voltage source as well as a triaxial 51 mm (2 in) sample holder.
84031 high resistance option
Some materials are characterized by very high resistances and can be difficult to measure in a traditional Hall measurement system. These materials include semi-insulating GaAs as well as photo-detectors and solid state x-ray detectors. This option provides a resistance measurement range from 10 kΩ up to 100 GΩ. Includes a Keithley 6514 electrometer, buffers to minimize loading, and a signal lead guard to minimize the effect of current leakage.